Add Moving Average to Excel Files Online

What types of moving average does the Excel moving average tool calculate?

Simple Moving Average (SMA, equal weight to all values in the window) and Exponential Moving Average (EMA, more weight to recent values). Both require a window size. The result is appended as a new column alongside the original data.

What window size should I use for a moving average on a Excel file?

Common choices are 7 for a weekly rolling average on daily data, 30 for a monthly rolling average, or 12 for a yearly rolling average on monthly data. Smaller windows react faster to changes; larger windows produce a smoother trend but lag behind recent movements.

How are the first rows handled in the Excel moving average — the rows without enough history?

Rows that do not have enough prior rows to fill the window receive NULL by default. Enable the partial window option to compute the average over however many rows are available at the start of the series instead of leaving them null.

Is my data private?

Yes — completely. Your file is never uploaded to any server. Everything runs locally in your browser using WebAssembly — processing happens entirely inside your tab. Once you close the tab, nothing is retained.

What is the maximum file size?

The free limit is 50 MB. For larger files, performance depends on your device's available memory — most modern machines handle 500 MB to 1 GB comfortably.