You can use either of the following formulas to subtract 30 minutes from a time in Excel:

**Formula 1: Use Mathematical Calculation**

=B2-(30/1440)

This particular formula subtracts 30 minutes from the time in cell **B2**.

Note that this formula divides 30 by the number of minutes in a day (1,440) because otherwise Excel will attempt to subtract 30 *days* instead of *minutes*.

**Formula 2: Use TIME Function**

=B2-TIME(0, 30, 0)

This particular formula also subtracts 30 minutes from the time in cell **B2**.

Both formulas produce the same results and both formulas work with times *and* datetimes in Excel.

The following examples show how to use each formula in practice with the following dataset that contains information about the time when various projects are due:

**Example 1: Subtract 30 Minutes from Time Using ****Mathematical Calculation**

We can type the following formula into cell **C2** to subtract 30 minutes from the time in cell **B2**:

=B2-(30/1440)

We can then click and drag this formula down to each remaining cell in column B:

The times in column C represent the times in column B with 30 minutes subtracted from them.

**Example 2: ****Subtract 30 Minutes from Time Using ****TIME Function**

We can type the following formula into cell **C2** to subtract 30 minutes from the time in cell **B2**:

=B2-TIME(0, 30, 0)

We can then click and drag this formula down to each remaining cell in column B:

The times in column C represent the times in column B with 30 minutes subtracted from them.

Note that the **TIME(Hour, Minute, Second)** function can be used to add or subtract a specific number of hours, minutes and seconds from a time.

By using **TIME(0, 30, 0)** we are able to subtract exactly 30 minutes from each time.

**Note**: You can find the complete documentation for the **TIME** function in Excel here.

**Additional Resources**

The following tutorials explain how to perform other common operations 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