Maintenance & Reliability worked example

Unplanned Downtime Percentage at 3.45% unplanned downtime target: a worked example

Push unplanned downtime target up to 3.45% and the picture changes. This example computes every intermediate figure at that operating point. Use it in daily production meetings and bad-actor review to show how much time failures are stealing from the schedule.

The inputs for this scenario

  • Unplanned downtime hours: 22 hr (unchanged)
  • Total available hours: 720 hr (unchanged)
  • Unplanned downtime target: 3.45 % (raised for this scenario; the documented default is 3)

Working through the calculation

  • Applying the documented formula (Unplanned downtime percentage = unplanned downtime hours ÷ total available hours × 100) to the inputs above produces each figure below.
  • At this operating point the engine returns 3.06 % for unplanned downtime share, the number this scenario is built around.
  • At this operating point the engine returns 0.39 points for gap to unplanned downtime target.
  • At this operating point the engine returns 22 count for unplanned downtime hours.
  • At this operating point the engine returns 720 count for available hours.

How this compares with the baseline

  • Against the tool's baseline example, where unplanned downtime target sits at 3% and the headline result is 3.06 %, this scenario lands almost exactly on the baseline at 3.06 %.
  • It divides unplanned downtime hours by total available hours and multiplies by 100, then subtracts the actual from your target to show the gap in percentage points. 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

  • Unplanned Downtime Share: 3.06 % (headline result)
  • Gap to Unplanned Downtime Target: 0.39 points
  • Unplanned Downtime Hours: 22 count
  • Available Hours: 720 count

Run it with your numbers

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

Last reviewed 2026-05-12.