Excel 2013 works with time values much the same way as any number, including the ability to subtract times to find the time difference.

Showing a time difference in hours, minutes and seconds isn't always convenient. If you are processing a large number of time differences as part of a testing experiment, for example, the values may be easier to work with if you have Excel convert them to decimal values. The default decimal value is based on a 24-hour unit, however you can change this to a 1-hour, 1-minute or 1-second unit as needed.

Open a blank worksheet. Drag the cursor over cells **C1**, **C2** and **C3** to highlight them. Click the **Home** tab and select **Time** from the **Number** menu to display the time in hours, minutes and seconds. For other Time format options, click the small **Arrow** at the bottom of the ribbon's Number section and select any Time format desired.

Enter a start time in cell **C1** and the end time in cell **C2**. In cell **C3**, type **=(C2-C1)** to subtract the stop time from the start time.

Press **Enter** to complete the formula. Excel subtracts the start time from the end time.

Type **=(C2-C1)** in cell **C4** and press **Enter**. Click the **Home** tab and change the **Number** menu to **Number**. Excel converts the time difference to decimal format, based on one day. For example, 24 hours would be 1.0 and 12 hours would be 0.5.

Click the **Increase Decimal** icon in the Numbers section of the Home ribbon if the decimal unit is too small to get an accurate result.

Highlight cells **C4** and **C5** and change the **Number** menu to **Number**.

Type **=(C2-C1)*24** in cell **C5** and press **Enter**. Multiplying the time difference by 24 displays the result as a decimal unit based on one hour. For example, 45 minutes would be 0.75 and two hours would be 2.0.

Type **=(C2-C1) 2460** in cell

**C6**and press

**Enter**. This creates a decimal unit based on one minute. Alternatively, you could multiply the value by 1440.

To calculate a decimal value based on one second, use **=(C2-C1)*86400**.

Change the start and end times. Excel automatically recalculates the time difference in each cell you entered a formula.