Smooth a series by averaging each value with its neighbors.
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=AVERAGE(B2:B4)A moving average averages a sliding window of rows (here three) and is filled down so the window moves with each row. It smooths noisy trends like daily sales. Widen the range for a longer, smoother window.
=AVERAGE(B2:B8)→1,240A 7-period moving average.
=AVERAGE({10,20,30})→20Average of three consecutive periods.
=AVERAGE(OFFSET(B2, COUNT(B:B)-3, 0, 3, 1))→1,310Always averages the last three values, even as new rows are added.
Average rows on both sides, e.g. =AVERAGE(B1:B3) aligned to B2 for a 3-period centered window.
A short window such as 3 reacts quickly to changes. A longer window such as 12 gives a smoother line but lags further behind.
Right-click the data series, choose Add Trendline, select Moving Average and set the period.
Return a blank until enough rows exist: =IF(ROW()<4, "", AVERAGE(B2:B4)) for a 3-period average that starts in row 4.
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