Aftermarket, Field Service & Service Parts worked example

Field Failure Rate at 1.08% target field failure rate: a worked example

Suppose target field failure rate falls to 1.08%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Calculate field failure rate from failed installed units, active installed units, and a reliability target.

The inputs for this scenario

  • Failed installed units: 128 units (held at the documented default)
  • Active installed units: 6,200 units (held at the documented default)
  • Target field failure rate: 1.08 % (the input this scenario stresses; the baseline uses 1.5)

Working through the calculation

  • The calculation starts from the formula this tool documents: Field failure rate = failed installed units ÷ active installed units × 100.
  • Field failure rate works out to 2.06 % failure rate at these inputs, and this is the headline figure for the scenario.
  • Failure-rate gap to target works out to -0.98 percentage points at these inputs.
  • Failed installed units works out to 128 units at these inputs.
  • Active installed units works out to 6,200 units at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where target field failure rate sits at 1.5% and the headline result is 2.06 % failure rate, this scenario lands almost exactly on the baseline at 2.06 % failure rate.
  • It divides failed installed units by the active installed base and multiplies by 100, then compares that rate against your reliability 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

  • Field failure rate: 2.06 % failure rate (headline result)
  • Failure-rate gap to target: -0.98 percentage points
  • Failed installed units: 128 units
  • Active installed units: 6,200 units

Run it with your numbers

  • To rerun this with your own numbers, open the live Field Failure Rate calculator, set target field failure rate to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.