The Easy Way to Add to the QAT

The easiest way to add an icon to the QAT is to right-click the icon in the Ribbon and choose Add to Quick Access Toolbar.

Open the Calculation Options drop-down and right-click Manual Calculation, choosing Add To Quick Access Toolbar. Repeat for Automatic calculation.

Adding Formulas, Calculation Options, Manual to the QAT gives you a clear indication of when your workbook is in Manual calculation mode:

When added to the QAT, Automatic and Manual appear with a checkbox and provide an awesome visual indicator that you are not in Automatic calculation mode.