S&OP, Demand Planning & Forecasting worked example

Customer Forecast Reliability at 99% forecast attainment: a worked example

Push forecast attainment up to 99% and the picture changes. This example computes every intermediate figure at that operating point. Use it when customer forecast reliability in s and op, demand planning and forecasting is being asked to take on more work and you need to know if there is room.

The inputs for this scenario

  • Forecast Units per Planning Cycle: 4 units / cycle (unchanged)
  • Number of Planning Cycles Available: 480 cycles (unchanged)
  • Forecast Attainment (uptime equivalent): 99 % (raised for this scenario; the documented default is 90)
  • Usable-Forecast Rate (first-pass yield): 97 % (unchanged)

Working through the calculation

  • Applying the documented formula (Gross customer forecast reliability capacity = customer forecast reliability output per cycle × available customer forecast reliability cycles) to the inputs above produces each figure below.
  • At this operating point the engine returns 1,844 units for good customer forecast reliability capacity, the number this scenario is built around.
  • At this operating point the engine returns 1,920 units for gross customer forecast reliability capacity.
  • At this operating point the engine returns 19.2 units for customer forecast reliability downtime loss.
  • At this operating point the engine returns 57.02 units for customer forecast reliability yield loss.

How this compares with the baseline

  • Against the tool's baseline example, where forecast attainment sits at 90% and the headline result is 1,676 units, this scenario comes in 10% above the baseline at 1,844 units.
  • It discounts a gross customer forecast by a forecast-attainment rate and a usable-forecast rate to yield the dependable volume you can safely plan against. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Good customer forecast reliability capacity: 1,844 units (headline result)
  • Gross customer forecast reliability capacity: 1,920 units
  • Customer forecast reliability downtime loss: 19.2 units
  • Customer forecast reliability yield loss: 57.02 units

Run it with your numbers

  • Every input above is editable in the live Customer Forecast Reliability calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.