To save time, particularly when you are making entries into a large workbook with many formulas, you can switch from automatic to manual recalculation; that is, Excel will recalculate only when you tell it to.

To set manual recalculation, choose Tools, Options and then click the Calculation tab to display the options.

Here are a few things to remember about calculation options:

1. To turn off automatic recalculation, select the Manual option. If you make a change that normally initiates recalculation, the status bar displays Calculate instead of recalculating automatically.

2. The Recalculate Before Save option helps make sure that the most current values are stored on disk.

3. To turn off automatic recalculation only for data tables, select the Automatic Except Tables option.

4. To recalculate all open workbooks, click the Calc Now button or press F9.

5. To calculate only the active worksheet in a workbook, click the Calc Sheet button or press Shift+F9.