Advanced Planning, Scheduling & APS worked example

Order Promise Date Buffer at 99% promise confidence level: a worked example

What does the result look like when promise confidence level reaches 99%? The full calculation is worked below with real intermediate numbers. a planner or customer service lead needs a defensible buffer before committing a ship or completion date

The inputs for this scenario

  • Open order quantity or load: 34 orders or hr (unchanged)
  • Promise time per order: 5.5 hr / order (unchanged)
  • Promise confidence level: 99 % (raised for this scenario; the documented default is 90)
  • Fixed calendar buffer: 24 hr (unchanged)

Working through the calculation

  • Applying the documented formula (Confidence-adjusted order load = open order load × promise time per order × promise confidence level) to the inputs above produces each figure below.
  • At this operating point the engine returns 209 promise buffer hr for promise-date buffer requirement, the number this scenario is built around.
  • At this operating point the engine returns 6.15 hr / order for promise time per order.
  • At this operating point the engine returns 185 promise buffer hr for confidence-adjusted order load.
  • At this operating point the engine returns 24 hr for fixed calendar buffer.

How this compares with the baseline

  • Against the tool's baseline example, where promise confidence level sits at 90% and the headline result is 192 promise buffer hr, this scenario comes in 8.75% above the baseline at 209 promise buffer hr.
  • A figure at this level is achievable when promise confidence level is genuinely sustained, not just peaked for a shift. It treats the confidence level as a simple multiplier on load rather than a true statistical service level, so it approximates rather than guarantees on-time delivery.

Results at a glance

  • Promise-date buffer requirement: 209 promise buffer hr (headline result)
  • Promise time per order: 6.15 hr / order
  • Confidence-adjusted order load: 185 promise buffer hr
  • Fixed calendar buffer: 24 hr

Run it with your numbers

  • Every input above is editable in the live Order Promise Date Buffer calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.