Moving Average Calculator

This calculator computes four different rolling statistics from up to ten sequential Period values: Simple Moving Average (lines 14-25, the unweighted mean of the last Window Size periods), Exponential Moving Average (lines 27-36, a recursive formula that seeds from Period 1 and then blends each subsequent period in at multiplier = EMA Smoothing Factor / (Window Size + 1)), Cumulative Moving Average (lines 44-49, the running mean of every period entered so far, independent of Window Size), and Weighted Moving Average (lines 52-61, a linearly-weighted mean over the last Window Size periods that gives the most recent period the largest weight). At the defaults, EMA Smoothing Factor is completely inert for Simple, Cumulative, and Weighted Moving Average — none of their formulas reference it, since it only appears in the EMA multiplier (line 28). Window Size is likewise inert for Cumulative Moving Average, which always averages the full period history regardless of how the window is set (lines 44-49 never read windowSize).

Period 10, the most recent data point, dominates Exponential Moving Average's sensitivity — not because it happens to be a large number, but because EMA's recursive blending (line 33) structurally weights the most recent input the heaviest, a genuine recency-weighting mechanism unlike Simple Moving Average's flat window average, where the "dominant" input is only dominant because its default magnitude (26) happens to exceed its window-mates' (19 and 24). This calculator does not detect trend breaks, seasonality, or outliers — it only smooths, so a sudden one-period spike still fully enters every average that includes it.