Demand forecasting
Forecast Horizon
By the Supply Chain Manager team · Updated October 16, 2026
The forecast horizon is how far into the future a forecast looks, for example the next 14 days, the next quarter or the next year.
Accuracy usually falls as the horizon lengthens. For replenishment, the horizon that matters most is the lead time plus the review period, because that is how far ahead today's order has to cover.
It helps to distinguish the frozen part of the horizon, where orders are already placed and cannot change, from the part you can still influence. Forecast effort and accuracy reviews should focus on the window just beyond the frozen zone, because that is where today's decisions take effect.
Forecast horizon example
Illustrative: a SKU with a 30-day import lead time and monthly ordering needs a forecast at least 60 days out to size today's order. A 14-day forecast, however accurate, does not see far enough.
Why forecast horizon matters for distributors
Matching the horizon to lead times keeps forecasting effort pointed at decisions you can still change. Longer horizons serve budgeting and capacity planning, where less precision is acceptable.
Common forecast horizon mistakes
- Judging a model's accuracy at one horizon and using it at another.
- Using a short-horizon forecast for long-lead-time imports.
Examples on this page use made-up round numbers to show the calculation. They are not benchmarks or results from real businesses.