Introduction

The Carbon class is inherited from the PHP DateTime class.

<?php
namespace Carbon;

class Carbon extends \DateTime
{
    // code here
}

Carbon has all of the functions inherited from the base DateTime class. This approach allows you to access the base functionality if you see anything missing in Carbon but is there in DateTime.

You can see from the code snippet above that the Carbon class is declared in the Carbon namespace. You need to import the namespace to use Carbon without having to provide its fully qualified name each time.

use Carbon\Carbon;

Note: I live in Ottawa, Ontario, Canada and if the timezone is not specified in the examples then the default of 'America/Toronto' is to be assumed. Typically Ottawa is -0500 but when daylight savings time is on we are -0400.

Special care has been taken to ensure timezones are handled correctly, and where appropriate are based on the underlying DateTime implementation. For example all comparisons are done in UTC or in the timezone of the datetime being used.

$dtToronto = Carbon::createFromDate(2012, 1, 1, 'America/Toronto');
$dtVancouver = Carbon::createFromDate(2012, 1, 1, 'America/Vancouver');

echo $dtVancouver->diffInHours($dtToronto); // 3

Also is comparisons are done in the timezone of the provided Carbon instance. For example my current timezone is -13 hours from Tokyo. So Carbon::now('Asia/Tokyo')->isToday() would only return false for any time past 1 PM my time. This doesn't make sense since now() in tokyo is always today in Tokyo. Thus the comparison to now() is done in the same timezone as the current instance.

Instantiation

There are several different methods available to create a new instance of Carbon. First there is a constructor. It overrides the parent constructor and you are best to read about the first parameter from the PHP manual and understand the date/time string formats it accepts. You'll hopefully find yourself rarely using the constructor but rather relying on the explicit static methods for improved readability.

$carbon = new Carbon();                  // equivalent to Carbon::now()
$carbon = new Carbon('first day of January 2008', 'America/Vancouver');
echo get_class($carbon);                 // 'Carbon\Carbon'
$carbon = Carbon::now(-5);

You'll notice above that the timezone (2nd) parameter was passed as a string and an integer rather than a \DateTimeZone instance. All DateTimeZone parameters have been augmented so you can pass a DateTimeZone instance, string or integer offset to GMT and the timezone will be created for you. This is again shown in the next example which also introduces the now() function.

$now = Carbon::now();

$nowInLondonTz = Carbon::now(new DateTimeZone('Europe/London'));

// or just pass the timezone as a string
$nowInLondonTz = Carbon::now('Europe/London');

// or to create a date with a timezone of +1 to GMT during DST then just pass an integer
echo Carbon::now(1)->tzName;             // Europe/London

If you really love your fluid method calls and get frustrated by the extra line or ugly pair of brackets necessary when using the constructor you'll enjoy the parse method.

echo (new Carbon('first day of December 2008'))->addWeeks(2);     // 2008-12-15 00:00:00
echo Carbon::parse('first day of December 2008')->addWeeks(2);    // 2008-12-15 00:00:00

To accompany now(), a few other static instantiation helpers exist to create widely known instances. The only thing to really notice here is that today(), tomorrow() and yesterday(), besides behaving as expected, all accept a timezone parameter and each has their time value set to 00:00:00.

$now = Carbon::now();
echo $now;                               // 2016-06-24 15:18:34
$today = Carbon::today();
echo $today;                             // 2016-06-24 00:00:00
$tomorrow = Carbon::tomorrow('Europe/London');
echo $tomorrow;                          // 2016-06-25 00:00:00
$yesterday = Carbon::yesterday();
echo $yesterday;                         // 2016-06-23 00:00:00

The next group of static helpers are the createXXX() helpers. Most of the static create functions allow you to provide as many or as few arguments as you want and will provide default values for all others. Generally default values are the current date, time or timezone. Higher values will wrap appropriately but invalid values will throw an InvalidArgumentException with an informative message. The message is obtained from an DateTime::getLastErrors() call.

Carbon::createFromDate($year, $month, $day, $tz);
Carbon::createFromTime($hour, $minute, $second, $tz);
Carbon::create($year, $month, $day, $hour, $minute, $second, $tz);

createFromDate() will default the time to now. createFromTime() will default the date to today. create() will default any null parameter to the current respective value. As before, the $tz defaults to the current timezone and otherwise can be a DateTimeZone instance or simply a string timezone value. The only special case for default values (mimicking the underlying PHP library) occurs when an hour value is specified but no minutes or seconds, they will get defaulted to 0.

$xmasThisYear = Carbon::createFromDate(null, 12, 25);  // Year defaults to current year
$Y2K = Carbon::create(2000, 1, 1, 0, 0, 0);
$alsoY2K = Carbon::create(1999, 12, 31, 24);
$noonLondonTz = Carbon::createFromTime(12, 0, 0, 'Europe/London');

// A two digit minute could not be found
try { Carbon::create(1975, 5, 21, 22, -2, 0); } catch(InvalidArgumentException $x) { echo $x->getMessage(); }

Carbon::createFromFormat($format, $time, $tz);

createFromFormat() is mostly a wrapper for the base php function DateTime::createFromFormat. The difference being again the $tz argument can be a DateTimeZone instance or a string timezone value. Also, if there are errors with the format this function will call the DateTime::getLastErrors() method and then throw a InvalidArgumentException with the errors as the message. If you look at the source for the createXX() functions above, they all make a call to createFromFormat().

echo Carbon::createFromFormat('Y-m-d H', '1975-05-21 22')->toDateTimeString(); // 1975-05-21 22:00:00

The final two create functions are for working with unix timestamps. The first will create a Carbon instance equal to the given timestamp and will set the timezone as well or default it to the current timezone. The second, createFromTimestampUTC(), is different in that the timezone will remain UTC (GMT). The second acts the same as Carbon::createFromFormat('@'.$timestamp) but I have just made it a little more explicit. Negative timestamps are also allowed.

echo Carbon::createFromTimestamp(-1)->toDateTimeString();                        // 1969-12-31 18:59:59
echo Carbon::createFromTimestamp(-1, 'Europe/London')->toDateTimeString();       // 1970-01-01 00:59:59
echo Carbon::createFromTimeStampUTC(-1)->toDateTimeString();                     // 1969-12-31 23:59:59

You can also create a copy() of an existing Carbon instance. As expected the date, time and timezone values are all copied to the new instance.

$dt = Carbon::now();
echo $dt->diffInYears($dt->copy()->addYear());  // 1

// $dt was unchanged and still holds the value of Carbon:now()

Finally, if you find yourself inheriting a \DateTime instance from another library, fear not! You can create a Carbon instance via a friendly instance() function.

$dt = new \DateTime('first day of January 2008'); // <== instance from another API
$carbon = Carbon::instance($dt);
echo get_class($carbon);                               // 'Carbon\Carbon'
echo $carbon->toDateTimeString();                      // 2008-01-01 00:00:00

A quick note about microseconds. The PHP DateTime object allows you to set a microsecond value but ignores it for all of its date math. As of 1.12.0 Carbon now supports microseconds during instantiation or copy operations as well as by default with the format() method.

$dt = Carbon::parse('1975-05-21 22:23:00.123456');
echo $dt->micro;                                       // 123456
echo $dt->copy()->micro;                               // 123456

Ever need to loop through some dates to find the earliest or latest date? Didn't know what to set your initial maximum/minimum values to? There are now two helpers for this to make your decision simple:

echo Carbon::maxValue();                               // '2038-01-18 22:14:07'
echo Carbon::minValue();                               // '1901-12-13 15:45:52'

Localization

Unfortunately the base class DateTime does not have any localization support. To begin localization support a formatLocalized($format) method was added. The implementation makes a call to strftime using the current instance timestamp. If you first set the current locale with PHP function setlocale() then the string returned will be formatted in the correct locale.

setlocale(LC_TIME, 'German');
echo $dt->formatLocalized('%A %d %B %Y');          // Mittwoch 21 Mai 1975
setlocale(LC_TIME, '');
echo $dt->formatLocalized('%A %d %B %Y');          // Wednesday 21 May 1975

diffForHumans() has also been localized. You can set the Carbon locale by using the static Carbon::setLocale() function.

Carbon::setLocale('de');
echo Carbon::now()->addYear()->diffForHumans();    // in 1 Jahr

Carbon::setLocale('en');

on Linux
If you have trouble with translations, check locales installed in your system (local and production).
locale -a to list locales enabled.
sudo locale-gen fr_FR.UTF-8 to install a new locale.
sudo dpkg-reconfigure locales to publish all locale enabled.
And reboot your system.

Testing Aids

The testing methods allow you to set a Carbon instance (real or mock) to be returned when a "now" instance is created. The provided instance will be returned specifically under the following conditions:

  • A call to the static now() method, ex. Carbon::now()
  • When a null (or blank string) is passed to the constructor or parse(), ex. new Carbon(null)
  • When the string "now" is passed to the constructor or parse(), ex. new Carbon('now')

$knownDate = Carbon::create(2001, 5, 21, 12);          // create testing date
Carbon::setTestNow($knownDate);                        // set the mock (of course this could be a real mock object)
echo Carbon::now();                                    // 2001-05-21 12:00:00
echo new Carbon();                                     // 2001-05-21 12:00:00
echo Carbon::parse();                                  // 2001-05-21 12:00:00
echo new Carbon('now');                                // 2001-05-21 12:00:00
echo Carbon::parse('now');                             // 2001-05-21 12:00:00
var_dump(Carbon::hasTestNow());                        // bool(true)
Carbon::setTestNow();                                  // clear the mock
var_dump(Carbon::hasTestNow());                        // bool(false)
echo Carbon::now();                                    // 2016-06-24 15:18:34

A more meaning full example:

class SeasonalProduct
{
    protected $price;

    public function __construct($price)
    {
        $this->price = $price;
    }

    public function getPrice() {
        $multiplier = 1;
        if (Carbon::now()->month == 12) {
            $multiplier = 2;
        }

        return $this->price * $multiplier;
    }
}

$product = new SeasonalProduct(100);
Carbon::setTestNow(Carbon::parse('first day of March 2000'));
echo $product->getPrice();                                             // 100
Carbon::setTestNow(Carbon::parse('first day of December 2000'));
echo $product->getPrice();                                             // 200
Carbon::setTestNow(Carbon::parse('first day of May 2000'));
echo $product->getPrice();                                             // 100
Carbon::setTestNow();

Relative phrases are also mocked according to the given "now" instance.

$knownDate = Carbon::create(2001, 5, 21, 12);          // create testing date
Carbon::setTestNow($knownDate);                        // set the mock
echo new Carbon('tomorrow');                           // 2001-05-22 00:00:00  ... notice the time !
echo new Carbon('yesterday');                          // 2001-05-20 00:00:00
echo new Carbon('next wednesday');                     // 2001-05-23 00:00:00
echo new Carbon('last friday');                        // 2001-05-18 00:00:00
echo new Carbon('this thursday');                      // 2001-05-24 00:00:00
Carbon::setTestNow();                                  // always clear it !

The list of words that are considered to be relative modifiers are:

  • this
  • next
  • last
  • tomorrow
  • yesterday
  • +
  • -
  • first
  • last
  • ago

Be aware that similar to the next(), previous() and modify() methods some of these relative modifiers will set the time to 00:00:00.

Getters

The getters are implemented via PHP's __get() method. This enables you to access the value as if it was a property rather than a function call.

$dt = Carbon::parse('2012-9-5 23:26:11.123789');

// These getters specifically return integers, ie intval()
var_dump($dt->year);                                         // int(2012)
var_dump($dt->month);                                        // int(9)
var_dump($dt->day);                                          // int(5)
var_dump($dt->hour);                                         // int(23)
var_dump($dt->minute);                                       // int(26)
var_dump($dt->second);                                       // int(11)
var_dump($dt->micro);                                        // int(123789)
var_dump($dt->dayOfWeek);                                    // int(3)
var_dump($dt->dayOfYear);                                    // int(248)
var_dump($dt->weekOfMonth);                                  // int(1)
var_dump($dt->weekOfYear);                                   // int(36)
var_dump($dt->daysInMonth);                                  // int(30)
var_dump($dt->timestamp);                                    // int(1346901971)
var_dump(Carbon::createFromDate(1975, 5, 21)->age);          // int(41) calculated vs now in the same tz
var_dump($dt->quarter);                                      // int(3)

// Returns an int of seconds difference from UTC (+/- sign included)
var_dump(Carbon::createFromTimestampUTC(0)->offset);         // int(0)
var_dump(Carbon::createFromTimestamp(0)->offset);            // int(-18000)

// Returns an int of hours difference from UTC (+/- sign included)
var_dump(Carbon::createFromTimestamp(0)->offsetHours);       // int(-5)

// Indicates if day light savings time is on
var_dump(Carbon::createFromDate(2012, 1, 1)->dst);           // bool(false)
var_dump(Carbon::createFromDate(2012, 9, 1)->dst);           // bool(true)

// Indicates if the instance is in the same timezone as the local timezone
var_dump(Carbon::now()->local);                              // bool(true)
var_dump(Carbon::now('America/Vancouver')->local);           // bool(false)

// Indicates if the instance is in the UTC timezone
var_dump(Carbon::now()->utc);                                // bool(false)
var_dump(Carbon::now('Europe/London')->utc);                 // bool(false)
var_dump(Carbon::createFromTimestampUTC(0)->utc);            // bool(true)

// Gets the DateTimeZone instance
echo get_class(Carbon::now()->timezone);                     // DateTimeZone
echo get_class(Carbon::now()->tz);                           // DateTimeZone

// Gets the DateTimeZone instance name, shortcut for ->timezone->getName()
echo Carbon::now()->timezoneName;                            // America/Toronto
echo Carbon::now()->tzName;                                  // America/Toronto

Setters

The following setters are implemented via PHP's __set() method. Its good to take note here that none of the setters, with the obvious exception of explicitly setting the timezone, will change the timezone of the instance. Specifically, setting the timestamp will not set the corresponding timezone to UTC.

$dt = Carbon::now();

$dt->year = 1975;
$dt->month = 13;             // would force year++ and month = 1
$dt->month = 5;
$dt->day = 21;
$dt->hour = 22;
$dt->minute = 32;
$dt->second = 5;

$dt->timestamp = 169957925;  // This will not change the timezone

// Set the timezone via DateTimeZone instance or string
$dt->timezone = new DateTimeZone('Europe/London');
$dt->timezone = 'Europe/London';
$dt->tz = 'Europe/London';

Fluent Setters

No arguments are optional for the setters, but there are enough variety in the function definitions that you shouldn't need them anyway. Its good to take note here that none of the setters, with the obvious exception of explicitly setting the timezone, will change the timezone of the instance. Specifically, setting the timestamp will not set the corresponding timezone to UTC.

$dt = Carbon::now();

$dt->year(1975)->month(5)->day(21)->hour(22)->minute(32)->second(5)->toDateTimeString();
$dt->setDate(1975, 5, 21)->setTime(22, 32, 5)->toDateTimeString();
$dt->setDateTime(1975, 5, 21, 22, 32, 5)->toDateTimeString();

$dt->timestamp(169957925)->timezone('Europe/London');

$dt->tz('America/Toronto')->setTimezone('America/Vancouver');

IsSet

The PHP function __isset() is implemented. This was done as some external systems (ex. Twig) validate the existence of a property before using it. This is done using the isset() or empty() method. You can read more about these on the PHP site: __isset(), isset(), empty().

var_dump(isset(Carbon::now()->iDoNotExist));       // bool(false)
var_dump(isset(Carbon::now()->hour));              // bool(true)
var_dump(empty(Carbon::now()->iDoNotExist));       // bool(true)
var_dump(empty(Carbon::now()->year));              // bool(false)

String Formatting

All of the available toXXXString() methods rely on the base class method DateTime::format(). You'll notice the __toString() method is defined which allows a Carbon instance to be printed as a pretty date time string when used in a string context.

$dt = Carbon::create(1975, 12, 25, 14, 15, 16);

var_dump($dt->toDateTimeString() == $dt);          // bool(true) => uses __toString()
echo $dt->toDateString();                          // 1975-12-25
echo $dt->toFormattedDateString();                 // Dec 25, 1975
echo $dt->toTimeString();                          // 14:15:16
echo $dt->toDateTimeString();                      // 1975-12-25 14:15:16
echo $dt->toDayDateTimeString();                   // Thu, Dec 25, 1975 2:15 PM

// ... of course format() is still available
echo $dt->format('l jS \\of F Y h:i:s A');         // Thursday 25th of December 1975 02:15:16 PM

You can also set the default __toString() format (which defaults to Y-m-d H:i:s) thats used when type juggling occurs.

Carbon::setToStringFormat('jS \o\f F, Y g:i:s a');
echo $dt;                                          // 25th of December, 1975 2:15:16 pm
Carbon::resetToStringFormat();
echo $dt;                                          // 1975-12-25 14:15:16

Note: For localization support see the Localization section.

Common Formats

The following are wrappers for the common formats provided in the DateTime class.

$dt = Carbon::now();

// $dt->toAtomString() is the same as $dt->format(DateTime::ATOM);
echo $dt->toAtomString();      // 1975-12-25T14:15:16-05:00
echo $dt->toCookieString();    // Thursday, 25-Dec-1975 14:15:16 EST
echo $dt->toIso8601String();   // 1975-12-25T14:15:16-0500
echo $dt->toRfc822String();    // Thu, 25 Dec 75 14:15:16 -0500
echo $dt->toRfc850String();    // Thursday, 25-Dec-75 14:15:16 EST
echo $dt->toRfc1036String();   // Thu, 25 Dec 75 14:15:16 -0500
echo $dt->toRfc1123String();   // Thu, 25 Dec 1975 14:15:16 -0500
echo $dt->toRfc2822String();   // Thu, 25 Dec 1975 14:15:16 -0500
echo $dt->toRfc3339String();   // 1975-12-25T14:15:16-05:00
echo $dt->toRssString();       // Thu, 25 Dec 1975 14:15:16 -0500
echo $dt->toW3cString();       // 1975-12-25T14:15:16-05:00

Comparison

Simple comparison is offered up via the following functions. Remember that the comparison is done in the UTC timezone so things aren't always as they seem.

echo Carbon::now()->tzName;                        // America/Toronto
$first = Carbon::create(2012, 9, 5, 23, 26, 11);
$second = Carbon::create(2012, 9, 5, 20, 26, 11, 'America/Vancouver');

echo $first->toDateTimeString();                   // 2012-09-05 23:26:11
echo $first->tzName;                               // America/Toronto
echo $second->toDateTimeString();                  // 2012-09-05 20:26:11
echo $second->tzName;                              // America/Vancouver

var_dump($first->eq($second));                     // bool(true)
var_dump($first->ne($second));                     // bool(false)
var_dump($first->gt($second));                     // bool(false)
var_dump($first->gte($second));                    // bool(true)
var_dump($first->lt($second));                     // bool(false)
var_dump($first->lte($second));                    // bool(true)

$first->setDateTime(2012, 1, 1, 0, 0, 0);
$second->setDateTime(2012, 1, 1, 0, 0, 0);         // Remember tz is 'America/Vancouver'

var_dump($first->eq($second));                     // bool(false)
var_dump($first->ne($second));                     // bool(true)
var_dump($first->gt($second));                     // bool(false)
var_dump($first->gte($second));                    // bool(false)
var_dump($first->lt($second));                     // bool(true)
var_dump($first->lte($second));                    // bool(true)

To determine if the current instance is between two other instances you can use the aptly named between() method. The third parameter indicates if an equal to comparison should be done. The default is true which determines if its between or equal to the boundaries.

$first = Carbon::create(2012, 9, 5, 1);
$second = Carbon::create(2012, 9, 5, 5);
var_dump(Carbon::create(2012, 9, 5, 3)->between($first, $second));          // bool(true)
var_dump(Carbon::create(2012, 9, 5, 5)->between($first, $second));          // bool(true)
var_dump(Carbon::create(2012, 9, 5, 5)->between($first, $second, false));   // bool(false)

Woah! Did you forget min() and max() ? Nope. That is covered as well by the suitably named min() and max() methods. As usual the default parameter is now if null is specified.

$dt1 = Carbon::create(2012, 1, 1, 0, 0, 0);
$dt2 = Carbon::create(2014, 1, 30, 0, 0, 0);
echo $dt1->min($dt2);                              // 2012-01-01 00:00:00

$dt1 = Carbon::create(2012, 1, 1, 0, 0, 0);
$dt2 = Carbon::create(2014, 1, 30, 0, 0, 0);
echo $dt1->max($dt2);                              // 2014-01-30 00:00:00

// now is the default param
$dt1 = Carbon::create(2000, 1, 1, 0, 0, 0);
echo $dt1->max();                                  // 2016-06-24 15:18:34

To handle the most used cases there are some simple helper functions that hopefully are obvious from their names. For the methods that compare to now() (ex. isToday()) in some manner the now() is created in the same timezone as the instance.

$dt = Carbon::now();

$dt->isWeekday();
$dt->isWeekend();
$dt->isYesterday();
$dt->isToday();
$dt->isTomorrow();
$dt->isFuture();
$dt->isPast();
$dt->isLeapYear();
$dt->isSameDay(Carbon::now());
$born = Carbon::createFromDate(1987, 4, 23);
$noCake = Carbon::createFromDate(2014, 9, 26);
$yesCake = Carbon::createFromDate(2014, 4, 23);
$overTheHill = Carbon::now()->subYears(50);
var_dump($born->isBirthday($noCake));              // bool(false)
var_dump($born->isBirthday($yesCake));             // bool(true)
var_dump($overTheHill->isBirthday());              // bool(true) -> default compare it to today!

Addition and Subtraction

The default DateTime provides a couple of different methods for easily adding and subtracting time. There is modify(), add() and sub(). modify() takes a magical date/time format string, 'last day of next month', that it parses and applies the modification while add() and sub() use a DateInterval class thats not so obvious, new \DateInterval('P6YT5M'). Hopefully using these fluent functions will be more clear and easier to read after not seeing your code for a few weeks. But of course I don't make you choose since the base class functions are still available.

$dt = Carbon::create(2012, 1, 31, 0);

echo $dt->toDateTimeString();            // 2012-01-31 00:00:00

echo $dt->addYears(5);                   // 2017-01-31 00:00:00
echo $dt->addYear();                     // 2018-01-31 00:00:00
echo $dt->subYear();                     // 2017-01-31 00:00:00
echo $dt->subYears(5);                   // 2012-01-31 00:00:00

echo $dt->addMonths(60);                 // 2017-01-31 00:00:00
echo $dt->addMonth();                    // 2017-03-03 00:00:00 equivalent of $dt->month($dt->month + 1); so it wraps
echo $dt->subMonth();                    // 2017-02-03 00:00:00
echo $dt->subMonths(60);                 // 2012-02-03 00:00:00

echo $dt->addDays(29);                   // 2012-03-03 00:00:00
echo $dt->addDay();                      // 2012-03-04 00:00:00
echo $dt->subDay();                      // 2012-03-03 00:00:00
echo $dt->subDays(29);                   // 2012-02-03 00:00:00

echo $dt->addWeekdays(4);                // 2012-02-09 00:00:00
echo $dt->addWeekday();                  // 2012-02-10 00:00:00
echo $dt->subWeekday();                  // 2012-02-09 00:00:00
echo $dt->subWeekdays(4);                // 2012-02-03 00:00:00

echo $dt->addWeeks(3);                   // 2012-02-24 00:00:00
echo $dt->addWeek();                     // 2012-03-02 00:00:00
echo $dt->subWeek();                     // 2012-02-24 00:00:00
echo $dt->subWeeks(3);                   // 2012-02-03 00:00:00

echo $dt->addHours(24);                  // 2012-02-04 00:00:00
echo $dt->addHour();                     // 2012-02-04 01:00:00
echo $dt->subHour();                     // 2012-02-04 00:00:00
echo $dt->subHours(24);                  // 2012-02-03 00:00:00

echo $dt->addMinutes(61);                // 2012-02-03 01:01:00
echo $dt->addMinute();                   // 2012-02-03 01:02:00
echo $dt->subMinute();                   // 2012-02-03 01:01:00
echo $dt->subMinutes(61);                // 2012-02-03 00:00:00

echo $dt->addSeconds(61);                // 2012-02-03 00:01:01
echo $dt->addSecond();                   // 2012-02-03 00:01:02
echo $dt->subSecond();                   // 2012-02-03 00:01:01
echo $dt->subSeconds(61);                // 2012-02-03 00:00:00

For fun you can also pass negative values to addXXX(), in fact that's how subXXX() is implemented.

P.S. Don't worry if you forget and use addDay(5) or subYear(3), I have your back ;)

Difference

These functions always return the total difference expressed in the specified time requested. This differs from the base class diff() function where an interval of 61 seconds would be returned as 1 minute and 1 second via a DateInterval instance. The diffInMinutes() function would simply return 1. All values are truncated and not rounded. Each function below has a default first parameter which is the Carbon instance to compare to, or null if you want to use now(). The 2nd parameter again is optional and indicates if you want the return value to be the absolute value or a relative value that might have a - (negative) sign if the passed in date is less than the current instance. This will default to true, return the absolute value. The comparisons are done in UTC.

// Carbon::diffInYears(Carbon $dt = null, $abs = true)

echo Carbon::now('America/Vancouver')->diffInSeconds(Carbon::now('Europe/London')); // 0

$dtOttawa = Carbon::createFromDate(2000, 1, 1, 'America/Toronto');
$dtVancouver = Carbon::createFromDate(2000, 1, 1, 'America/Vancouver');
echo $dtOttawa->diffInHours($dtVancouver);                             // 3

echo $dtOttawa->diffInHours($dtVancouver, false);                      // 3
echo $dtVancouver->diffInHours($dtOttawa, false);                      // -3

$dt = Carbon::create(2012, 1, 31, 0);
echo $dt->diffInDays($dt->copy()->addMonth());                         // 31
echo $dt->diffInDays($dt->copy()->subMonth(), false);                  // -31

$dt = Carbon::create(2012, 4, 30, 0);
echo $dt->diffInDays($dt->copy()->addMonth());                         // 30
echo $dt->diffInDays($dt->copy()->addWeek());                          // 7

$dt = Carbon::create(2012, 1, 1, 0);
echo $dt->diffInMinutes($dt->copy()->addSeconds(59));                  // 0
echo $dt->diffInMinutes($dt->copy()->addSeconds(60));                  // 1
echo $dt->diffInMinutes($dt->copy()->addSeconds(119));                 // 1
echo $dt->diffInMinutes($dt->copy()->addSeconds(120));                 // 2

echo $dt->addSeconds(120)->secondsSinceMidnight();                     // 120

There are also special filter functions diffInDaysFiltered(), diffInHoursFiltered() and diffFiltered(), to help you filter the difference by days, hours or a custom interval. For example to count the weekend days between two instances:

$dt = Carbon::create(2014, 1, 1);
$dt2 = Carbon::create(2014, 12, 31);
$daysForExtraCoding = $dt->diffInDaysFiltered(function(Carbon $date) {
   return $date->isWeekend();
}, $dt2);

echo $daysForExtraCoding;      // 104

$dt = Carbon::create(2014, 1, 1)->startOfDay();
$dt2 = $dt->copy()->endOfDay();
$littleHandRotations = $dt->diffFiltered(CarbonInterval::minute(), function(Carbon $date) {
   return $date->minute === 0;
}, $dt2);

echo $littleHandRotations;     // 24

// others that are defined
// diffInYears(), diffInMonths(), diffInWeeks()
// diffInDays(), diffInWeekdays(), diffInWeekendDays()
// diffInHours(), diffInMinutes(), diffInSeconds()
// secondsSinceMidnight(), secondsUntilEndOfDay()

Difference for Humans

It is easier for humans to read 1 month ago compared to 30 days ago. This is a common function seen in most date libraries so I thought I would add it here as well. It uses approximations for a month being 4 weeks. The lone argument for the function is the other Carbon instance to diff against, and of course it defaults to now() if not specified.

This method will add a phrase after the difference value relative to the instance and the passed in instance. There are 4 possibilities:

  • When comparing a value in the past to default now:
    • 1 hour ago
    • 5 months ago
  • When comparing a value in the future to default now:
    • 1 hour from now
    • 5 months from now
  • When comparing a value in the past to another value:
    • 1 hour before
    • 5 months before
  • When comparing a value in the future to another value:
    • 1 hour after
    • 5 months after

You may also pass true as a 2nd parameter to remove the modifiers ago, from now, etc : diffForHumans(Carbon $other, true).

// The most typical usage is for comments
// The instance is the date the comment was created and its being compared to default now()
echo Carbon::now()->subDays(5)->diffForHumans();               // 5 days ago

echo Carbon::now()->diffForHumans(Carbon::now()->subYear());   // 1 year after

$dt = Carbon::createFromDate(2011, 8, 1);

echo $dt->diffForHumans($dt->copy()->addMonth());              // 1 month before
echo $dt->diffForHumans($dt->copy()->subMonth());              // 1 month after

echo Carbon::now()->addSeconds(5)->diffForHumans();            // 5 seconds from now

echo Carbon::now()->subDays(24)->diffForHumans();              // 3 weeks ago
echo Carbon::now()->subDays(24)->diffForHumans(null, true);    // 3 weeks

You can also change the locale of the string using Carbon::setLocale('fr') before the diffForHumans() call. See the localization section for more detail.

Modifiers

These group of methods perform helpful modifications to the current instance. Most of them are self explanatory from their names... or at least should be. You'll also notice that the startOfXXX(), next() and previous() methods set the time to 00:00:00 and the endOfXXX() methods set the time to 23:59:59.

The only one slightly different is the average() function. It moves your instance to the middle date between itself and the provided Carbon argument.

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->startOfDay();                            // 2012-01-31 00:00:00

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->endOfDay();                              // 2012-01-31 23:59:59

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->startOfMonth();                          // 2012-01-01 00:00:00

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->endOfMonth();                            // 2012-01-31 23:59:59

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->startOfYear();                           // 2012-01-01 00:00:00

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->endOfYear();                             // 2012-12-31 23:59:59

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->startOfDecade();                         // 2010-01-01 00:00:00

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->endOfDecade();                           // 2019-12-31 23:59:59

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->startOfCentury();                        // 2000-01-01 00:00:00

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->endOfCentury();                          // 2099-12-31 23:59:59

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->startOfWeek();                           // 2012-01-30 00:00:00
var_dump($dt->dayOfWeek == Carbon::MONDAY);        // bool(true) : ISO8601 week starts on Monday

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->endOfWeek();                             // 2012-02-05 23:59:59
var_dump($dt->dayOfWeek == Carbon::SUNDAY);        // bool(true) : ISO8601 week ends on Sunday

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->next(Carbon::WEDNESDAY);                 // 2012-02-01 00:00:00
var_dump($dt->dayOfWeek == Carbon::WEDNESDAY);     // bool(true)

$dt = Carbon::create(2012, 1, 1, 12, 0, 0);
echo $dt->next();                                  // 2012-01-08 00:00:00

$dt = Carbon::create(2012, 1, 31, 12, 0, 0);
echo $dt->previous(Carbon::WEDNESDAY);             // 2012-01-25 00:00:00
var_dump($dt->dayOfWeek == Carbon::WEDNESDAY);     // bool(true)

$dt = Carbon::create(2012, 1, 1, 12, 0, 0);
echo $dt->previous();                              // 2011-12-25 00:00:00

$start = Carbon::create(2014, 1, 1, 0, 0, 0);
$end = Carbon::create(2014, 1, 30, 0, 0, 0);
echo $start->average($end);                        // 2014-01-15 12:00:00

// others that are defined that are similar
//   firstOfMonth(), lastOfMonth(), nthOfMonth()
//   firstOfQuarter(), lastOfQuarter(), nthOfQuarter()
//   firstOfYear(), lastOfYear(), nthOfYear()

Constants

The following constants are defined in the Carbon class.

// These getters specifically return integers, ie intval()
var_dump(Carbon::SUNDAY);                          // int(0)
var_dump(Carbon::MONDAY);                          // int(1)
var_dump(Carbon::TUESDAY);                         // int(2)
var_dump(Carbon::WEDNESDAY);                       // int(3)
var_dump(Carbon::THURSDAY);                        // int(4)
var_dump(Carbon::FRIDAY);                          // int(5)
var_dump(Carbon::SATURDAY);                        // int(6)

var_dump(Carbon::YEARS_PER_CENTURY);               // int(100)
var_dump(Carbon::YEARS_PER_DECADE);                // int(10)
var_dump(Carbon::MONTHS_PER_YEAR);                 // int(12)
var_dump(Carbon::WEEKS_PER_YEAR);                  // int(52)
var_dump(Carbon::DAYS_PER_WEEK);                   // int(7)
var_dump(Carbon::HOURS_PER_DAY);                   // int(24)
var_dump(Carbon::MINUTES_PER_HOUR);                // int(60)
var_dump(Carbon::SECONDS_PER_MINUTE);              // int(60)

$dt = Carbon::createFromDate(2012, 10, 6);
if ($dt->dayOfWeek === Carbon::SATURDAY) {
    echo 'Place bets on Ottawa Senators Winning!';
}

CarbonInterval

The Carbon class is inherited from the PHP DateInterval class.

<?php
class CarbonInterval extends \DateInterval
{
    // code here
}

You can create an instance in the following ways:

echo CarbonInterval::year();                           // 1 year
echo CarbonInterval::months(3);                        // 3 months
echo CarbonInterval::days(3)->seconds(32);             // 3 days 32 seconds
echo CarbonInterval::weeks(3);                         // 3 weeks
echo CarbonInterval::days(23);                         // 3 weeks 2 days
echo CarbonInterval::create(2, 0, 5, 1, 1, 2, 7);      // 2 years 5 weeks 1 day 1 hour 2 minutes 7 seconds

If you find yourself inheriting a \DateInterval instance from another library, fear not! You can create a CarbonInterval instance via a friendly instance() function.

$di = new \DateInterval('P1Y2M'); // <== instance from another API
$ci = CarbonInterval::instance($di);
echo get_class($ci);                                   // 'Carbon\CarbonInterval'
echo $ci;                                              // 1 year 2 months

Other helpers, but beware the implemenation provides helpers to handle weeks but only days are saved. Weeks are calculated based on the total days of the current instance.

echo CarbonInterval::year()->years;                    // 1
echo CarbonInterval::year()->dayz;                     // 0
echo CarbonInterval::days(24)->dayz;                   // 24
echo CarbonInterval::days(24)->daysExcludeWeeks;       // 3
echo CarbonInterval::weeks(3)->days(14)->weeks;        // 2  <-- days setter overwrites the current value
echo CarbonInterval::weeks(3)->weeks;                  // 3
echo CarbonInterval::minutes(3)->weeksAndDays(2, 5);   // 2 weeks 5 days 3 minutes

It also has a handy forHumans(), which is mapped as the __toString() implementation, that prints the interval for humans.

CarbonInterval::setLocale('fr');
echo CarbonInterval::create(2, 1)->forHumans();        // 2 ans 1 mois
echo CarbonInterval::hour()->seconds(3);               // 1 heure 3 secondes
CarbonInterval::setLocale('en');

As you can see, you can change the locale of the string using CarbonInterval::setLocale('fr').