Subtract hours from a time

You can subtract (or add) a number of hours from a time using fractions.
Dates are represented as sequential whole numbers so 1 hour is equivalent to the fraction (1/24).
Times are represented as fractions based on there being 24 hours in a day.
1 Hour is 1/24 = 0.04166
1 Minute is 1/(24*60) = 1/1440
1 Second is 1/(24*60*60) = 1/86400

	A
1	=TODAY() = Friday 29 November 2024
2	=NOW() = Friday 29 November 2024 11:44:05
3	=A2 - (6/24) = Friday, 29 November, 2024 05:44 AM
4	=A2 - TIME(6, 0, 0) = Friday, 29 November, 2024 05:44 AM
5	=A2 - (8/24)-(15/1440) = Friday, 29 November, 2024 03:29 AM
6	=A2 - TIME(8, 15, 0) = Friday, 29 November, 2024 03:29 AM
7	=A2 - (13/24) - (25/(1440)) , (45/86400) = Thursday, 28 November, 2024 10:18 PM
8	=A2 - TIME(13, 25, 45) = Thursday, 28 November, 2024 10:18 PM

1 - Displays the current date. Custom format "dddd dd mmmm yyyy".
2 - Displays the current date and time. Custom format "dddd dd mmmm yyyy hh:mm:ss".
3 - Displays the current time minus 6 hours.
4 - Displays the current time minus 6 hours using the TIME function to return the correct decimal.
5 - Displays the current time minus 8 hours and 15 minutes.
6 - Displays the current time minus 8 hours and 15 minutes using the TIME function to return the correct decimal.
7 - Displays the current time minus 13 hours, 25 minutes and 45 seconds.
8 - Displays the current time minus 13 hours, 25 minutes and 45 seconds using the TIME function to return the correct decimal.
All these cells have been formatted with the custom number format "dddd, dd mmmm, yyyy hh:mm AM/PM".

Built-in Functions

NOW - The date serial number of the current system date and time.
TIME - The time as a decimal given an hour, minute, second.
TODAY - The date serial number representing today's date.

Related Formulas

Add hours to a time
Subtract minutes from a time
Subtract seconds from a time