How do you calculate the demand forecast gap?

Subtract required demand from available (forecasted) demand, then divide by the reference baseline. With 125 forecast, 100 required, and a 100 baseline, the gap is 25 divided by 100, or a 25% forecast gap.

What is a good demand forecast gap for specialty films?

Closer to zero is better. Mature S&OP processes often run forecast error in the low double digits or single digits at the family level; a persistent 25% gap signals meaningful bias worth correcting, especially on long-lead barrier substrates.

Does a positive gap mean I'm over-forecasting?

Yes. A positive gap like the 25% here means forecast exceeds actual demand, which tends to build excess roll inventory. A negative gap means you under-forecast and risk stockouts and expedites on long-lead materials.

Forecast gap vs forecast accuracy - what's the difference?

They are two views of the same error. The gap keeps the sign so you see direction and bias; accuracy is usually reported as one hundred percent minus the absolute error. Use the gap when you care whether you are running high or low.

Which baseline should I use for the reference amount?

Use a stable, meaningful denominator - most often the required or actual demand, or an average demand for the family. Keep the baseline consistent period to period so the percentages stay comparable.

Why does the forecast gap matter more for barrier films?

Barrier resins, metallized layers, and specialty substrates carry long lead times and finite shelf life, so an over-forecast ages inventory and an under-forecast triggers costly expedites. Small percentage gaps become large dollar swings.

Specialty Films, Membranes & Barrier Materials calculator

Demand Forecast Gap Calculator

The demand forecast gap measures how far your barrier-film or membrane demand forecast sits above or below actual firm orders, expressed as a percentage of a baseline. Planners and S&OP leads in the specialty-films business use it to see whether they are over-forecasting - and building excess roll inventory that ties up cash and ages toward its shelf life - or under-forecasting and risking stockouts on long-lead resins and metallized substrates. Because barrier films often carry long procurement lead times and finite shelf life, even a modest forecast gap translates into real inventory or expedite cost. Tracking the gap over time exposes forecast bias before it hits the P&L.

What this calculator does

Estimate demand forecast gap for specialty films, membranes and barrier materials using production-ready inputs so teams can measure the gap between available and required amounts.
Use it when demand forecast gap in specialty films, membranes and barrier materials needs a clean margin number for a specialty films, membranes and barrier materials go / no-go review.
It computes the difference between forecasted and required demand, then expresses that gap as a percentage of a reference baseline.

Formula used

Demand forecast gap amount gap = available demand forecast gap amount - required demand forecast gap amount
Demand forecast gap margin = amount gap ÷ reference demand forecast gap amount

Inputs explained

Forecasted or committed barrier-film demand:
Actual firm orders or consumption:
Baseline demand used for the comparison:

How to use the result

Use it in the S&OP or demand-review cycle to size forecast error, spot over- or under-forecasting, and decide whether to adjust production or inventory targets.
A single-period gap can be noise; it reflects only the three amounts you enter and does not distinguish a systematic bias from normal demand variability without a trend behind it.

Current U.S. benchmarks

The producer price index for plastic resins and materials stands at 319.371 (BLS, May 2026), up 19.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.
Global copper trades at $13,484 per tonne (IMF via FRED, May 2026), up 41.5% in a year, and U.S. industrial electricity averages 8.66 cents per kWh. Both feed electrified-hardware unit economics.

Common questions

How do you calculate the demand forecast gap? Subtract required demand from available (forecasted) demand, then divide by the reference baseline. With 125 forecast, 100 required, and a 100 baseline, the gap is 25 divided by 100, or a 25% forecast gap.
What is a good demand forecast gap for specialty films? Closer to zero is better. Mature S&OP processes often run forecast error in the low double digits or single digits at the family level; a persistent 25% gap signals meaningful bias worth correcting, especially on long-lead barrier substrates.
Does a positive gap mean I'm over-forecasting? Yes. A positive gap like the 25% here means forecast exceeds actual demand, which tends to build excess roll inventory. A negative gap means you under-forecast and risk stockouts and expedites on long-lead materials.
Forecast gap vs forecast accuracy - what's the difference? They are two views of the same error. The gap keeps the sign so you see direction and bias; accuracy is usually reported as one hundred percent minus the absolute error. Use the gap when you care whether you are running high or low.
Which baseline should I use for the reference amount? Use a stable, meaningful denominator - most often the required or actual demand, or an average demand for the family. Keep the baseline consistent period to period so the percentages stay comparable.

Last reviewed 2026-05-12.