A Moving Calculation is a table calculation that can be performed within Tableau. It aggregates values within the past or future to smooth a curve to neglect short time fluctuations from, most of the time, a line chart. This can help to detect interesting patterns behind the data, which you would not see with the regular visualization.
If you take a look at superstore sales on a daily level there are extreme fluctuations within the data (Fig.1).
On the Sales pill, you can click ‘Quick Table Calculation’ and ‘Moving Average’ and you’ll see how your chart changes. The Chart will look more flattened.
By clicking on ‘Edit Table Calculation’ on Sales, we can see how Tableau has calculated the formula (Fig.2).
The Calculation behind a moving average is shown in Fig.3.