S&OP, Demand Planning & Forecasting worked example

Service Level Buffer with average daily demand of 3,000 units / day: a worked example

What does the result look like when average daily demand reaches 3,000 units / day? The full calculation is worked below with real intermediate numbers. Use it when service level buffer in s and op, demand planning and forecasting is being sized for a buffer or safety stock review.

The inputs for this scenario

  • Average Daily Demand: 3,000 units / day (raised for this scenario; the documented default is 1,200)
  • Replenishment Lead Time: 85 days (unchanged)
  • Safety Stock Multiplier: 1.1 factor (unchanged)

Working through the calculation

  • Applying the documented formula (Service level buffer cycle stock = service level buffer daily usage × service level buffer lead time) to the inputs above produces each figure below.
  • At this operating point the engine returns 32.09 days for protected days of supply, the number this scenario is built around.
  • At this operating point the engine returns 35.29 days for unprotected days.
  • At this operating point the engine returns 3,000 pieces for inventory.
  • At this operating point the engine returns 85 pieces / day for daily usage.

How this compares with the baseline

  • Against the tool's baseline example, where average daily demand sits at 1,200 units / day and the headline result is 12.83 days, this scenario comes in 150% above the baseline at 32.09 days.
  • A figure at this level is achievable when average daily demand is genuinely sustained, not just peaked for a shift. A flat safety multiplier is a simplification — a statistically correct safety stock depends on demand and lead-time standard deviation and the service factor for your target fill rate, so treat the multiplier as an approximation of that.

Results at a glance

  • Protected days of supply: 32.09 days (headline result)
  • Unprotected days: 35.29 days
  • Inventory: 3,000 pieces
  • Daily usage: 85 pieces / day

Run it with your numbers

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

Last reviewed 2026-05-12.