Maintenance & Reliability worked example

MTTR with total repair hours of 240 hr: a worked example

Push total repair hours up to 240 hr and the picture changes. This example computes every intermediate figure at that operating point. Use it when evaluating repair efficiency, troubleshooting support needs, or the value of better access, spares, and procedures.

The inputs for this scenario

  • Total repair hours: 240 hr (raised for this scenario; the documented default is 96)
  • Number of repairs: 12 repairs (unchanged)
  • Normalization factor: 1 x (unchanged)

Working through the calculation

  • Applying the documented formula (MTTR = total repair hours รท number of repairs) to the inputs above produces each figure below.
  • At this operating point the engine returns 20 hr / repair for mttr, the number this scenario is built around.
  • At this operating point the engine returns 20 hr / repair for base repair time.
  • At this operating point the engine returns 1 x for normalization factor.
  • At this operating point the engine returns 12 value for repair count.

How this compares with the baseline

  • Against the tool's baseline example, where total repair hours sits at 96 hr and the headline result is 8 hr / repair, this scenario comes in 150% above the baseline at 20 hr / repair.
  • It computes the average repair duration by dividing total repair hours by the number of repairs, then applies an optional normalization factor. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • MTTR: 20 hr / repair (headline result)
  • Base Repair Time: 20 hr / repair
  • Normalization Factor: 1 x
  • Repair Count: 12 value

Run it with your numbers

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

Last reviewed 2026-05-12.