Glossary
Wrench time
Wrench time is the percentage of a technician's paid working hours actually spent performing repair, install, or maintenance work on site, as opposed to driving, waiting, or handling paperwork.
The formula.
Hands-on-the-job hours over total paid hours, for the same period.
- Benchmark
- None. There is no universal figure; track it against your own baseline.
- Read with
- Technician utilization (billable hours over paid hours) and windshield time (drive time between stops).
- Excluded
- Travel, staging at the shop and admin between jobs: paid time, so in the denominator, never the numerator.
Wrench time = hands-on-the-job hours ÷ total paid hours
What lowers wrench time
The biggest drags are usually windshield time from poor route sequencing, waiting on parts that weren't staged before the job, and paperwork — job notes, photos, signatures — done manually instead of captured in the field as part of the workflow. None of these require adding headcount to fix; they require better sequencing and less manual data entry.
Why wrench time matters for commercial contractors
Labor is the largest cost line for most commercial and mechanical service contractors, and wrench time is the cleanest measure of how much of that cost is actually converting into billable repair work. At scale — 10 to 200 techs across multiple branches — a small drop in wrench time compounds into a meaningful capacity gap, which shows up as backlog growth or missed SLA windows before it shows up on a P&L.
Where it lives, and what to read with it
Every work order status change — traveling, on site, in progress, complete — is timestamped automatically as the technician works the job, so wrench time rolls up per tech, per branch, and per equipment type without a separate time-tracking system. That same timeline feeds job costing, so labor cost and wrench time are always looking at the same underlying data.
Straight answers.
How is wrench time different from technician utilization?
Wrench time is hands-on-tool hours over paid hours. Technician utilization is billable hours over paid or available hours — a broader measure that can include diagnostic time or approved non-repair billable work that isn't strictly "wrench on the unit."
What's a good wrench time target?
There's no universal number — it depends on route density, job mix, and how much admin work is still manual. Treat it as a trend to improve against your own baseline rather than a published industry figure.
Does travel time count toward or against wrench time?
Travel is paid time but not wrench time — it sits in the denominator, not the numerator, which is exactly why windshield time is the metric most often paired with it.
How much does manual paperwork actually cost wrench time?
It varies by shop, but any time spent writing up a job, taking photos, or collecting a signature outside the field workflow is time not counted as wrench time — moving that into the mobile work order closes the gap directly.