You can use the following basic formulas to add and subtract hours from a time in Excel:
Formula 1: Add Hours to Time
=A1+(3/24)
This particular formula adds 3 hours to the time in cell A1.
Formula 2: Subtract Hours from Time
=A1-(3/24)
This particular formula subtracts 3 hours from the time in cell A1.
This formula works with times and datetimes in Excel.
Note: We must divide the number of hours by 24 because otherwise Excel will attempt to add or subtract 3 days instead of hours.
The following examples show how to use each formula in practice.
Example 1: Add & Subtract Hours from Time in Excel
The following screenshot shows how to add 3 hours to a column of time values in Excel:
The values in column B represent the values in column A with 3 hours added to them.
We can just as easily subtract 3 hours from each time value in column A as well:
The values in column B represent the values in column A with 3 hours subtracted from them.
Example 2: Add & Subtract Hours from DateTime in Excel
The following screenshot shows how to add 3 hours to a column of datetime values in Excel:
The datetime values in column B represent the datetime values in column A with 3 hours added to them.
We can just as easily subtract 3 hours from each datetime value in column A as well:
The datetime values in column B represent the datetime values in column A with 3 hours added to them.
Additional Resources
The following tutorials explain how to perform other common tasks in Excel:
How to Add & Subtract Weeks to Date in Excel
How to Convert Date to Month and Year Format in Excel
How to Calculate the Difference Between Two Dates in Excel