How to find the difference between two dates

Short answer

The diff() method returns the difference between two dates. The total number of days is in the days property:

<?php
 
$start = new DateTime('2025-01-01');
$end = new DateTime('2025-03-15');
 
echo $start->diff($end)->days;

Output:

73

Years, months and days

The difference is also available in parts — for example, to compute an age:

<?php
 
$diff = (new DateTime('2020-05-10'))->diff(new DateTime('2025-03-15'));
 
echo $diff->y, ' ', $diff->m, ' ', $diff->d;

Output:

4 10 5

Adding days to a date

The modify() method shifts a date by a given interval and takes month lengths into account:

<?php
 
$date = new DateTime('2025-01-30');
$date->modify('+5 days');
 
echo $date->format('Y-m-d');

Output:

2025-02-04