A running average is the mean of everything from the top through the current row — it smooths a series as it grows. An expanding AVERAGE range does it with one fill-down formula.
The example
The average updates as each value is added.
| A | B | |
|---|---|---|
| 1 | Value | Running avg |
| 2 | 10 | 10 |
| 3 | 20 | 15 |
| 4 | 30 | 20 |
The formula
The formula:
How it works
How it works:
AVERAGE($B$2:B2)averages from the locked top cell through the current row.- The absolute start and relative end make the range grow as you fill down.
- Unlike a moving average (fixed window), a running average includes every value so far.
- It’s the cumulative version of a running total — useful for tracking a stabilizing mean over time.
Running vs moving: a running average grows to include all history (smooths more over time); a moving average keeps a fixed window of the last N (responds to recent change). Pick the one that matches whether old data should keep mattering.
Try it: interactive demo
Values.
Variations
Moving average
Fixed window:
Running total
Additive:
Running count
How many so far:
Pitfalls & errors
Lock the start. Forgetting the $ on the first cell breaks the expanding range.
Blanks lower the count. AVERAGE skips blanks, so early gaps shift the mean.
Not a moving average. This includes all history, not just the recent window.
Practice workbook
Frequently asked questions
How do I make a running average in Excel?
What's the difference from a moving average?
Why is my running average off early on?
Stop fighting formulas. Learn them in a day.
This recipe is one of hundreds of real-world formulas we teach. Our Excel Formulas & Functions class covers lookups, logic, text, and dynamic arrays hands-on — live in Dallas–Fort Worth, Houston, Austin, Oklahoma City, Denver, or online.
See the Formulas & Functions Class