How to Subtract Time in PowerShell

To subtract time from the DateTime variable in PowerShell, you can use any of the below methods.

Method 1: Using the TimeSpan Add() method with a negative value

# define a DateTime object
$date = [DateTime] "2024-04-15 12:30:00 PM"

# Subtract 2 hours from the datetime object

$new_date = $date.Add([TimeSpan]::FromHours(-2))

Write-Output $new_date

This example will output the DateTime object with 2 hours subtracted.

Method 2: Using the Subtraction operator

# define a DateTime object
$date = [DateTime] "2024-04-15 12:30:00 PM"

# Subtract 2 hours from the datetime object

$new_date = $date - [TimeSpan]::FromHours(2)

Write-Output $new_date

This example will output the DateTime object with 2 hours subtracted from a datetime variable.

Method 3: Using the TimeSpan

# define a DateTime object
$date = [DateTime] "2024-04-15 12:30:00 PM"

# Subtract 2 hours 30 minutes from the datetime object

$new_date = $date - [TimeSpan]  '2:30'

Write-Output $new_date

This example will output the DateTime object with 2 hours and 30 minutes subtracted from a datetime variable.

The following examples show how you can use these methods.

Subtract Time from a DateTime Variable Using the TimeSpan Add() method

To subtract time in PowerShell from a datetime variable, you can use the TimeSpan struct and its Add() method.

# define a DateTime object
$date = [DateTime] "2024-04-15 12:30:00 PM"

# Subtract 2 hours from the datetime object

$new_date = $date.Add([TimeSpan]::FromHours(-2))

Write-Output $new_date

Output:

In this PowerShell script, the $date variable stores the datetime. We use the Add() method of TimeSpan struct to subtract 2 hours using the FromHours() method.

Finally, we output the DateTime object with 2 hours subtracted from a datetime variable $date.

Subtract Time Using the Subtraction Operator

You can use the Subtraction operator to subtract the specified amount of time ( 2 hours) from the given datetime object.

# define a DateTime object
$date = [DateTime] "2024-04-15 12:30:00 PM"

# Subtract 2 hours from the datetime object

$new_date = $date - [TimeSpan]::FromHours(2)

Write-Output $new_date

Output:

This PowerShell script uses the subtract operator (–) to subtract 2 hrs from the datetime variable and output to the console using the Write-Output cmdlet.

Subtract Time from DateTime Variable Using the TimeSpan

Another way to subtract time from a datetime variable is to use the TimeSpan struct and specify the amount of time to subtract.

# define a DateTime object
$date = [DateTime] "2024-04-15 12:30:00 PM"

# Subtract 2 hours 30 minutes from the datetime object

$new_date = $date - [TimeSpan]  '2:30'

Write-Output $new_date

Output:

This example outputs the date time object by subtracting 2 hours and 30 minutes from the $date variable.

Conclusion

I hope the above article on subtracting time from a datetime variable in PowerShell is helpful to you.

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