Mean time to repair
Mean time to repair (MTTR) is the average time it takes to return failed equipment to service once a repair is underway, calculated by dividing total repair downtime by the number of repairs completed in a period.
The inputs.
- Repair downtimeTotal time the equipment or site is out of service while a repair is in progress, measured from the start of the repair.
- Number of repairsRepairs completed in the same period — the count that turns total downtime into an average.
- Applies toRepairable units you fix and return to service. For assets you replace outright, mean time to failure is the matching number.
How to read MTTR.
How to calculate mean time to repair
MTTR equals total repair downtime divided by the number of repairs completed over the same period. "Repair downtime" is measured from when the repair starts — typically the technician's on-site clock-in — until the equipment is back in service, so it covers diagnosis, the work itself, and any time waiting on parts while the unit is down. It's a meaningful number only when start and stop times are actually recorded, which is why timestamped work orders matter more than estimating it after the fact.
Why MTTR matters for commercial contractors
On commercial and mechanical accounts, MTTR is the number behind how fast a customer's facility gets back to normal — a rooftop unit or chiller that's down is disrupting the customer's business, not just yours. It's also the repair-time component of the resolution windows written into SLAs, which means a slow MTTR shows up as missed SLA compliance before it shows up as a customer complaint. And because it's measured from the repair, it's the honest complement to how long the equipment runs in the first place.
What drives mean time to repair down
The biggest drags are usually parts availability — a repair that pauses waiting on a part can double or triple MTTR even with a good technician — followed by skill-to-job matching at dispatch and diagnostic accuracy from equipment service history. A technician who arrives with the right part and a clear history of the unit fixes it in one pass. MTTR is less about working faster and more about showing up ready to finish.
How Thermal tracks MTTR automatically
Work order status changes — dispatched, traveling, on site, in progress, complete — are timestamped as the technician works, so per-repair duration and MTTR roll up per equipment record, technician, and branch without a separate time log. The equipment record carries prior service history into the visit, and the dispatch board surfaces suggested technician matches by location and skill, which is where the readiness to finish the job is decided.
Questions attached to this term.
How is mean time to repair different from response time?
Response time is the clock from a request until a technician arrives on site. MTTR starts when the repair itself begins and runs until the equipment is back in service — so response time is about getting there, and MTTR is about getting it fixed.
Does MTTR include time spent waiting on parts?
It depends on how you define the repair window. If the clock runs from the start of the repair to the equipment back in service, then yes — which is exactly why parts availability is the lever that moves MTTR most.
What's a good mean time to repair benchmark?
There's no single defensible figure — it varies by equipment class, failure type, and how much on-site diagnosis is required. Track it as a trend against your own baseline rather than chasing a published number.
How is MTTR related to first-time fix rate?
A repair that takes two visits is both a high-MTTR event and a first-time-fix miss. The two metrics are driven by the same inputs — parts readiness and diagnostic accuracy on the first visit.
These numbers, on your own book.
If you want to see them calculated from real work orders and agreements rather than a spreadsheet, that's a demo.