DATA & ANALYSIS

Weighted Moving Average Demand Forecast Calculator

Estimate next-period demand from three consecutive historical periods using your own normalized relative weights.

Weighted demand forecast calculator

Estimate next-period demand from three consecutive historical periods using your own normalized relative weights.

How it works

Adjust the example values to match your scenario.

YOUR RESULT LIVE CALCULATION
Weighted moving-average baseline
126.667units / next period
THREE PERIODS, ENTERED WEIGHTS
Oldest period100 units
Middle period120 units
Most recent period140 units
Next-period baseline126.667 units
Simple three-period mean
120 units
Oldest period normalized weight
16.67%
Middle period normalized weight
33.33%
Most recent period normalized weight
50%

A simple unvalidated forecast baseline with no trend, seasonality, or uncertainty estimate. Periods must be consecutive and comparable.

BEHIND THE NUMBER

How the calculation works

Periods must have equal duration, the same item or cohort, and the same demand unit. Weights are normalized, so 1:2:3 and 10:20:30 are equivalent. A zero-weight observation is ignored; at least one weight must be positive. The forecast remains unrounded and is compared with a simple three-period mean.

Next forecast = (oldest demand x its weight + middle demand x its weight + latest demand x its weight) / total weight

When this calculation helps

A weighted forecast emphasizes selected historical observations under explicitly entered weights. Keep observations in time order and use the same demand unit and period length.

Check the interpretation

Weights do not learn seasonality or recognize a promotion automatically. A smoother historical series is not evidence of better future accuracy. Back-test against later actuals and inspect bias before replacing a planning forecast.

This is an unvalidated three-period baseline, not a trained predictive model. It does not infer trend, seasonality, promotions, stockout-censored demand, or confidence intervals. Back-test against actual demand before using it for replenishment.

MIT demand forecasting notes on weighted moving averages

Good to know

Must the newest observation have the largest weight?

No. The weights are your assumptions. More recent observations often receive more weight in a recency-based baseline, but the tool does not choose or validate those weights.

Is this the forecast accuracy tool?

No. This creates one next-period baseline. Forecast accuracy measures errors between already-issued forecasts and aligned actual observations.