Aftermarket, Field Service & Service Parts worked example

Parts Fill Rate at 99% target parts fill rate: a worked example

What does the result look like when target parts fill rate reaches 99%? The full calculation is worked below with real intermediate numbers. a parts inventory analyst needs to measure how well service stock is meeting demand

The inputs for this scenario

  • Service part lines filled from stock: 3,260 lines (unchanged)
  • Service part lines requested: 3,525 lines (unchanged)
  • Target parts fill rate: 99 % (raised for this scenario; the documented default is 95)

Working through the calculation

  • Applying the documented formula (Parts fill rate = service part lines filled from stock ÷ service part lines requested × 100) to the inputs above produces each figure below.
  • At this operating point the engine returns 92.48 % fill rate for parts fill rate, the number this scenario is built around.
  • At this operating point the engine returns 6.52 percentage points for fill-rate gap.
  • At this operating point the engine returns 3,260 lines for lines filled from stock.
  • At this operating point the engine returns 3,525 lines for lines requested.

How this compares with the baseline

  • Against the tool's baseline example, where target parts fill rate sits at 95% and the headline result is 92.48 % fill rate, this scenario lands almost exactly on the baseline at 92.48 % fill rate.
  • A figure at this level is achievable when target parts fill rate is genuinely sustained, not just peaked for a shift. It measures line availability, not first-time-fix outcomes; a part can be in stock but at the wrong location, so pair fill rate with location-level and first-time-fix data.

Results at a glance

  • Parts fill rate: 92.48 % fill rate (headline result)
  • Fill-rate gap: 6.52 percentage points
  • Lines filled from stock: 3,260 lines
  • Lines requested: 3,525 lines

Run it with your numbers

  • Every input above is editable in the live Parts Fill Rate calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.