How to Add and Subtract 30 Minutes to a Time String in PHP

For clarity, you're aiming to manipulate a time value formatted as "H:i" by adding and subtracting 30 minutes. Let's delve into the process.

Defining the Function

$time = '10:00'; // Assuming 'H:i' format

// Calculate start and end times
$startTime = date("H:i", strtotime('-30 minutes', strtotime($time)));
$endTime = date("H:i", strtotime(' 30 minutes', strtotime($time)));

Explanation:

1. Convert the given time string to a timestamp using strtotime. This interpretation makes it easier to manipulate.
2. Use the strtotime function with an offset of -30 minutes to create a new timestamp representing 30 minutes before the original time. Then convert it back to a string in "H:i" format using date.
3. Perform a similar process for the end time, but with an offset of 30 minutes.

Result:

Running this code with an input time of '10:00' will generate the following:

$startTime = '09:30'
$endTime = '10:30'