Aftermarket, Field Service & Service Parts worked example

Parts Fill Rate at 68% target parts fill rate: a worked example

Suppose target parts fill rate falls to 68%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Calculate the share of service part demand filled immediately from available stock without backorder or substitution.

The inputs for this scenario

  • Service part lines filled from stock: 3,260 lines (held at the documented default)
  • Service part lines requested: 3,525 lines (held at the documented default)
  • Target parts fill rate: 68 % (the input this scenario stresses; the baseline uses 95)

Working through the calculation

  • The calculation starts from the formula this tool documents: Parts fill rate = service part lines filled from stock ÷ service part lines requested × 100.
  • Parts fill rate works out to 92.48 % fill rate at these inputs, and this is the headline figure for the scenario.
  • Fill-rate gap works out to -24.48 percentage points at these inputs.
  • Lines filled from stock works out to 3,260 lines at these inputs.
  • Lines requested works out to 3,525 lines at these inputs.

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.
  • It computes the share of requested service part lines filled immediately from stock and how that fill rate compares to your target. 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

  • Parts fill rate: 92.48 % fill rate (headline result)
  • Fill-rate gap: -24.48 percentage points
  • Lines filled from stock: 3,260 lines
  • Lines requested: 3,525 lines

Run it with your numbers

  • To rerun this with your own numbers, open the live Parts Fill Rate calculator, set target parts fill rate to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.