Suppose if you want to increment a cell by 1 to see how your formulae handle that change, may be a simulation. That means that cell would be incremented by 1 everytime you hit F9 (keyboard short cut to make Excel recalculate). To achieve this do the following:
1. On the Tools menu, click Options, and then click the Calculation tab.
2. Select the Iteration check box.
3. Set the maximum number of times Microsoft Excel will recalculate, type one as the number of iterations in the Maximum iterations box
-MS Excel Help
Then enter this formula in the cell which you want to increment, suppose it’s A1.
Formula for A1: =A1+1.
That’s it! Now, every time you hit F9, that cell will be incremented by 1. If you want it increment by some other number, use that number in the formula.