Forecast Accuracy Calculator
Forecast accuracy measures how close your demand forecasts are to actual demand. This calculator provides multiple accuracy metrics to help you evaluate and improve your forecasting process.
Input Parameters
Formula
Forecast Accuracy = 100% - |Forecast - Actual| / Actual × 100%Forecast accuracy is typically expressed as a percentage, where 100% means perfect accuracy. The formula calculates the absolute error as a percentage of actual demand.
Variable Definitions
Forecast Accuracy
How accurate the forecast was, expressed as a percentage.
Forecast Bias
Whether forecasts consistently over or under predict demand.
Absolute Error
The absolute difference between forecast and actual.
Example Calculation
Scenario: Comparing monthly forecast to actuals: - Forecast: 1,000 units - Actual: 950 units Absolute Error = |1,000 - 950| = 50 units Error % = 50 / 950 × 100% = 5.26% Forecast Accuracy = 100% - 5.26% = 94.74% Bias = (1,000 - 950) / 950 × 100% = +5.26% (over-forecasting)
How to Interpret Your Result
Understanding forecast accuracy: • 90%+ accuracy: Excellent for most industries • 80-90%: Good, typical for many product categories • 70-80%: Average, significant room for improvement • Below 70%: Poor, needs immediate attention Watch for bias - consistent over or under forecasting indicates systematic issues.