Adding and Subtracting Time
Move dates forward and back with addDays, subMonths and friends.
Syntax
$carbon->addDays(10)->subHours(2);Carbon makes date math effortless. Every unit has an add and sub method:
addDays()/subDays()addMonths()/subMonths()addHours()/subHours()
These return a new adjusted Carbon instance so you can chain them.
Example
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When to use it
- A subscription manager adds 30 days to now() with addDays(30) to compute the next billing date when a user subscribes to a monthly plan.
- An event countdown subtracts the current time from the event date using diffInHours() to display a live countdown timer on the page.
- A scheduler calls subWeeks(1) on a reminder date to send a one-week warning email before the deadline.
More examples
Add and subtract time units
Carbon provides addX() and subX() methods for every time unit (seconds through years), each returning a new instance.
use Carbon\Carbon;
$now = Carbon::now();
$now->addDays(30); // 30 days in the future
$now->subHours(6); // 6 hours in the past
$now->addMonths(3); // 3 months forward
$now->subYears(1); // one year agoCompute a subscription expiry date
Uses addMonths() to compute the expiry timestamp based on the chosen plan, storing both the start and end dates.
use Carbon\Carbon;
public function subscribe(User $user, string $plan): void
{
$duration = match ($plan) {
'monthly' => 1,
'yearly' => 12,
default => 1,
};
$user->update([
'subscribed_at' => now(),
'expires_at' => now()->addMonths($duration),
]);
}Clamp a date to start/end of period
startOfX() and endOfX() snap a Carbon instance to the precise beginning or end of a day, month, or other period.
use Carbon\Carbon;
$dt = Carbon::parse('2025-03-14 14:23:45');
$dt->startOfDay(); // 2025-03-14 00:00:00
$dt->endOfDay(); // 2025-03-14 23:59:59
$dt->startOfMonth(); // 2025-03-01 00:00:00
$dt->endOfMonth(); // 2025-03-31 23:59:59
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