PHP Date Exercises : Add/subtract the number of days from a particular date

Last update on June 03 2025 12:56:05 (UTC/GMT +8 hours)

16. Date Arithmetic: Add/Subtract Days

Write a PHP script to add/subtract the number of days from a particular date.

Sample Solution:

PHP Code:

<?php
$dt='2011-01-01'; // Assigning the date '2011-01-01' to the variable $dt.
echo 'Original date : '.$dt."\n"; // Outputting the original date.
$no_days = 40; // Setting the number of days to 40.
$bdate = strtotime("-".$no_days." days", strtotime($dt)); // Subtracting 40 days from the original date using strtotime function and storing the result in $bdate.
$adate = strtotime("+".$no_days." days", strtotime($dt)); // Adding 40 days to the original date using strtotime function and storing the result in $adate.
echo 'Before 40 days : '.date("Y-m-d", $bdate)."\n"; // Outputting the date 40 days before the original date.
echo 'After 40 days : '.date("Y-m-d", $adate)."\n"; // Outputting the date 40 days after the original date.
?>

Output:

Original date : 2011年01月01日 
Before 40 days : 2010年11月22日 
After 40 days : 2011年02月10日

Explanation:

In the exercise above,

• $dt='2011-01-01': Assign the date '2011-01-01' to the variable '$dt'.
• echo 'Original date : '.$dt."\n";: Outputting the original date stored in '$dt'.
• $no_days = the variable '$no_days' to 40.
• $bdate = strtotime("-".$no_days." days", strtotime($dt));: Subtracting 40 days from the original date using "strtotime()" function and storing the result in '$bdate'.
• $adate = strtotime("+".$no_days." days", strtotime($dt));: Adding 40 days to the original date using "strtotime()" function and storing the result in '$adate'.
• echo 'Before 40 days : '.date("Y-m-d", $bdate)."\n";: Outputting the date 40 days before the original date.
• echo 'After 40 days : '.date("Y-m-d", $adate)."\n";: Outputting the date 40 days after the original date.

Flowchart :

For more Practice: Solve these Related Problems:

• Write a PHP script to add a given number of days to a specified date using DateTime::modify() and display the new date.
• Write a PHP function that subtracts a number of days from a date and outputs both the original and modified dates.
• Write a PHP program to calculate the date 40 days before and after a given date, then print both results with labels.
• Write a PHP script to compare a modified date with the current date and output the difference in days.

Go to:

• PHP Date Exercises Home ↩
• PHP Exercises Home ↩

PREV : Check if Date is a Weekend.
NEXT : Start and End Date of Week by Week Number.

PHP Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.