How to Calculate a Running AVERAGE in Excel

What this does

AVERAGE adds the numbers in a range and divides by how many there are, ignoring blank and text cells (unlike a manual SUM/COUNT, which you would have to guard yourself). It is the arithmetic mean — the single value that best represents the centre of a tidy data set, though a few extreme values can drag it, which is when MEDIAN is the better choice. The same idea underpins a lot of everyday Excel work, so the few minutes spent getting it right here pay back across every sheet you build afterwards. Treat it as a pattern, not a one-off, and it stops being something you look up and starts being something you reach for. The difference between a quick fix and a sheet you can trust is the extra minute you spend validating “calculate a running average in excel”. Start on a copy or a tiny sample, keep the affected cells visible, and compare the result with the outcome you expected before you touch the real workbook. When a formula is involved, keep the inputs labelled beside it, reference cells instead of typing values, and apply number formatting only after the result checks out. The point is a calculation you can defend to a CFO or an auditor, but the practical win is that someone else can open the file and understand what happened without asking you.

A worked example

For the scores 12, 15, 9, 21, 17, 14 in A1:A6, =AVERAGE(A1:A6) returns 14.67. To average only passing scores, =AVERAGEIF(A1:A6,">=10") ignores the 9 and returns 15.8. If one score were a typo of 210, the average would leap to 47 — a reminder to check for outliers. The average is the first summary anyone asks for — typical sales, mean score, average response time. Knowing when it lies (skewed data, hidden blanks) is what separates a quick number from a trustworthy one. Check the referenced cells, argument order and result type in your workbook. Start with the worked example before changing an input, then compare the changed result with the calculation you expected. An error value or a result of a different type is a reason to inspect the inputs and arguments.

In Google Sheets

Google Sheets support for this task has not been verified. Check the function, arguments and workflow in the target product before transferring the example. Matching formula notation does not establish identical behaviour. The aim was to get you unstuck fast and leave you a little more capable than a copy-paste would. The answer is at the top and the detail above shows why it holds — so the next time a colleague asks, you can answer without reaching for search. For “calculate a running average in excel”, keep the input cells and the result visible while you check the formula in Excel. Follow the worked example and change one input at a time. The steps explain the workbook calculation; this page does not run a live calculator for that task.

Common mistakes

• Including blank cells you meant to count as zero — AVERAGE ignores blanks, changing the divisor.
• Letting a single outlier skew the mean; check with MEDIAN when data is lopsided.
• Averaging an already-averaged column (an average of averages) instead of the raw values.
• Counting text cells as zeros — AVERAGE skips them, which may not be what you intend.

Frequently asked questions