Holt's Linear Smoothing

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Tap a term to see what it means, or .

Calculate

Example: a shop's monthly sales, growing month by month. Simple smoothing always lags a step behind; Holt also tracks the trend. What to forecast for the next three months? Change the values to work out your own case.

Values of the series In order, separated by spaces or commas. Level weight α Trend weight β Periods ahead h

Step by step

What each term means

Forecast (x̂ₙ₊ₕ): The value forecast h periods after the last one observed.
Level (Lₙ): Where the series is now, without the noise. It is updated by blending the new value (weight α) with the previous forecast, level plus trend (weight 1 − α).
Horizon (h): How many periods ahead. The forecast moves h steps along the trend.
Trend (Tₙ): How much the series rises or falls per period. It is updated by blending the level's latest change (weight β) with the previous trend (weight 1 − β).