Often it is frustrating to figure out exactly how Excel arrives at a particular result-particularly if the formula returning the result is quite complex. Fortunately, Excel provides a tool you can use to help figure out what is going on when Excel evaluates a formula.
To use this tool, first select the cell that contains the formula you want evaluated. Then, display the Formulas tab of the ribbon. In the Formula Auditing group click the Evaluate Formula tool. Excel displays the Evaluate Formula dialog box. (See Figure 1.)
Figure 1. The Evaluate Formula dialog box.
At this point, Excel shows the full formula from the cell, and part of it is underlined. This underlined area represents the part of the formula that Excel will next evaluate. This allows you to see what intermediate steps Excel follows in arriving at a result. Every time you click the Evaluate button, Excel replaces the underlined portion of the formula with a result.
Nothing you do with the formula evaluator actually affects the formula in your worksheet; it remains unchanged. Instead, Excel simply shows you what happens as it works through each part of the formula to arrive at a result. When you are done using the formula evaluator, click the Close button.
It should be noted that the formula evaluator is for evaluating just what it says: formulas. It is not for evaluating other items, such as data points on charts or aggregated data in PivotTables.