DateInterval to prepare definite date and time for use in date time calculations in PHP

$date = new DateTime("2024-10-01");
$interval = new DateInterval("P1M"); // 1 month

$date->add($interval); // Adds 1 month
echo $date->format('Y-m-d'); // Output: 2024-11-01

DateInterval can be used to create a new dateinterval object for our date calculation and uses in any script. In the advance PHP object oriented style for all date & time calculations this format is useful. To specify we have to use some standards which are listed here. The period designations are single character.

Y  Year
M Month 
D days
H hours
I minutes
S seconds

The total specification has to start with P and then with an integer value followed by a period designator. All time part has to start with T.
Example : 4 days can be specified as P4D. Here are some more examples of datetime interval specifications

P7D : 7 days
P1Y1M  :  One year and one month
P1Y1M2D : One year, one month and 2 Days

We need to keep the sequence as Year Month and Date , we can't keep at Month Year Date or any other way as we wish.

P1Y2D1M : This is wrong sequence

Same way we can add time also to the sequence , let us try with time only, then we will add both date and time to the sequence

PT1H : Adds one hour to the present time 
PT1H5M : Adds one hour 5 minutes to the present time
PT1H5M10S : Adds one hour 5 minutes 10 seconds

Here also we have to maintain the sequence as Hour Minute and seconds .

PT1M5H10S

This will generate error as we have followed Minutes , Hour and second format. Let us combine date and time both and create an interval object

P1Y2M5DT1H5M10S

This will set an interval of 1 Year , 2 Months, 5 Days , 1 Hour, 5 Minutes, 10 Seconds

Adding date interval to date object

We will try to add the above interval to a new date object. Here is the php script.

$date = new DateTime('2012-02-01 13:25:50');
echo $date->format('Y-m-d H:i:s') . "<br>";
$date->add(new DateInterval('P1Y2M5DT1H5M10S'));
echo $date->format('Y-m-d H:i:s') . "\n";

The output of above code is here

2012-02-01 13:25:50
2013-04-06 14:31:00

Using today's date

In above code replace the first line.

$date = new DateTime(); // Todays date

Output ( Refresh this page and see the changes )

2026-12-22 15:25:34

PHP Date Functions Date Difference Timestamp in PHP Displaying calendar for selection of date by user Formatting the date interval in date and time

Subhendu Mohapatra

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DateInterval : represents a duration of time between two dates or time

Adding date interval to date object

Using today's date

Subhendu Mohapatra