How to Calculate a Year

1. Click on a blank cell where you want to enter your formula calculation and display the year-to-date average.
2. Begin your formula calculation by clicking the 'Average' function. You can find this formula in one of several places in different versions of Excel. In Excel 2010, it is easily accessible on the 'Auto Sum' menu, available on both the 'Home' tab and the 'Formulas' tab. Or you can always manually type in '=AVERAGE().'
3. Select the cells you want to use in the average. If they are all in the same row or column, click and drag your cursor across all of the cells you want. If they are not in the same row or column, click on them one by one while holding the 'CTRL' key on your keyboard. Also select the cells that you want to include as the year progresses and that do not have data in them yet. As soon as you enter the data, the program automatically includes it in the average. Be sure that these cells are blank, and do not display zeros or dashes; otherwise, the program calculates zeros into the average. Excel indicates which cells you have highlighted with colored lines as well as by displaying the cell numbers (such as 'A1, A2') in the cell where you are creating the formula.
4. Press the 'Enter' key on your keyboard to complete the formula. Excel calculates and displays the average in the cell where you put the formula calculation. Each time you enter data into the blank cells that you included in the formula, the running average changes accordingly.