MTBF & MTTR Calculator
Static · formula-only · worked example computed when this page was built · no live data
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%. Anything the worked example does not state uses this calculator's standard default; the interactive version shows every input and lets you change it.
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 by WorkHive's calculation engine when this page was built; standard: ISO 14224 | IEC 60050-192 | SMRP.
How to use this calculator
- Read the worked example. It uses a pump that ran 4,000 hours, failed 5 times, and took 40 hours of repair in total and shows every number in the method.
- Follow the formula with your own figures: it returns MTBF, MTTR, Availability, Failures, computed per ISO 14224 | IEC 60050-192 | SMRP.
- To compute interactively, open the MTBF & MTTR Calculator inside WorkHive's free Engineering Design suite (link below). It runs the same method with your inputs.
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, which is how long the asset runs before failing. MTTR measures maintainability, which is 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, and a free sign-up saves your calculations, BOMs and scope-of-works to your account.