MTBF & MTTR Calculator
The MTBF & MTTR Calculator computes Mean Time Between Failures, Mean Time To Repair, and the availability they produce together. Example: for a pump that ran 4,000 hours, failed 5 times, and took 40 hours of repair in total, MTBF = 800 h, MTTR = 8 h, Availability = 99 %, Failures = 5 (per ISO 14224 | IEC 60050-192 | SMRP).
How it works
MTBF = operating hours / number of failures. MTTR = total repair time / number of repairs. Availability = MTBF / (MTBF + MTTR). For the example: MTBF = 4000/5 = 800 h, MTTR = 40/5 = 8 h, Availability = 800/808 = 99.0%.
Worked example (Reliability & Metrics)
Inputs: a pump that ran 4,000 hours, failed 5 times, and took 40 hours of repair in total.
| Result | Value |
|---|---|
| MTBF | 800 h |
| MTTR | 8 h |
| Availability | 99 % |
| Failures | 5 |
Computed live by WorkHive's calculation engine; standard: ISO 14224 | IEC 60050-192 | SMRP.
How to use this calculator
- Enter the figures for the duty you are sizing: the worked example below uses a pump that ran 4,000 hours, failed 5 times, and took 40 hours of repair in total.
- The calculator returns MTBF, MTTR, Availability, Failures, computed per ISO 14224 | IEC 60050-192 | SMRP.
- Check the worked example to confirm the method matches how you would do it by hand, then run your own numbers in the interactive tool.
FAQ
How do you calculate MTBF?
Divide total operating hours by the number of failures in that period. A pump that ran 4,000 hours and failed 5 times has an MTBF of 800 hours.
How do you calculate MTTR?
Divide total repair time by the number of repairs. Five repairs totalling 40 hours gives an MTTR of 8 hours.
What is the difference between MTBF and MTTR?
MTBF measures reliability: how long the asset runs before failing. MTTR measures maintainability: how long it takes to restore. You raise MTBF with better preventive maintenance and root-cause fixes; you lower MTTR with spares availability and standard work.
How do MTBF and MTTR give availability?
Availability = MTBF / (MTBF + MTTR). With MTBF 800 h and MTTR 8 h, availability is 99.0%. That figure is also what feeds the availability factor inside OEE.
Run it on your own numbers
Open the interactive MTBF & MTTR Calculator in WorkHive: free, no sign-up needed for the calculators.