# MTTR, MTTD & MTBF calculator

Turn incident totals for a period into mean time to detect, to repair and between failures, plus the availability they imply.

## How it works

MTTD is the average time before someone knew, MTTR the average time to fix, and MTBF the average working time between incidents.

```
MTTR = repair time ÷ incidents
MTBF = (period − downtime) ÷ incidents
availability = MTBF ÷ (MTBF + MTTR)
```

## Questions

### Which one should I improve first?

Usually MTTD: you can’t fix what nobody has noticed, and better alerting shortens every incident.

### Do short blips count as incidents?

Count what you would review. Mixing tiny blips with real incidents makes the averages meaningless.

## Related tools

- [SLO & error budget calculator](https://powertraces.com/tools/slo-error-budget)
- [Burn-rate alert planner](https://powertraces.com/tools/burn-rate-alerts)
- [Uptime nines converter](https://powertraces.com/tools/uptime-nines)
- [Composite SLA calculator](https://powertraces.com/tools/composite-sla)

[All tools](https://powertraces.com/tools)