Calculation Warning

You have to be careful when turning off calculation in Excel. The calculation options are on the right of the Formulas ribbon tab – see image below.

When you turn off calculation (change it to Manual) it affects all the open files, not just the active one. The reasons you must be careful are

  • Most people don’t turn off calculation and hence always expect the sheets to automatically calculate, so they may rely on the results even though they might not have been updated.
  • When you save a file and calculation has been turned off, the file remembers the calculation state and when you or someone else opens the file it will turn off calculation which again causes the previous issue

When you turn off calculation always remember to turn it back on (change to Automatic) before you save the file.