S&OP, Demand Planning & Forecasting worked example

Monthly Forecast Volatility at 65% planning system availability: a worked example

Suppose planning system availability falls to 65%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Estimate monthly forecast volatility for sandop, demand planning and forecasting using production-ready inputs so teams can confirm whether capacity can cover demand before committing the schedule.

The inputs for this scenario

  • Forecast revisions processed per planning run: 4 units / cycle (held at the documented default)
  • Planning runs available in the month: 480 cycles (held at the documented default)
  • Planning system availability: 65 % (the input this scenario stresses; the baseline uses 90)
  • Revisions accepted without rework (first pass): 97 % (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Gross monthly forecast volatility capacity = monthly forecast volatility output per cycle × available monthly forecast volatility cycles.
  • Good monthly forecast volatility capacity works out to 1,211 units at these inputs, and this is the headline figure for the scenario.
  • Gross monthly forecast volatility capacity works out to 1,920 units at these inputs.
  • Monthly forecast volatility downtime loss works out to 672 units at these inputs.
  • Monthly forecast volatility yield loss works out to 37.44 units at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where planning system availability sits at 90% and the headline result is 1,676 units, this scenario comes in 27.78% below the baseline at 1,211 units.
  • It computes the number of forecast revisions your process can fully absorb per month after subtracting system-downtime losses and first-pass rework. When the numbers land here, the stressed input is the lever to work; the walkthrough above shows exactly how much each output recovers as it climbs back toward the baseline.

Results at a glance

  • Good monthly forecast volatility capacity: 1,211 units (headline result)
  • Gross monthly forecast volatility capacity: 1,920 units
  • Monthly forecast volatility downtime loss: 672 units
  • Monthly forecast volatility yield loss: 37.44 units

Run it with your numbers

  • To rerun this with your own numbers, open the live Monthly Forecast Volatility calculator, set planning system availability to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.