Time on site is the elapsed time from when a technician arrives at a job to when they mark it done. It includes the work, plus everything else that happens at the address: talking to the customer, diagnosis, fetching parts from the truck, cleanup and payment.
The formula
Time on site = Done timestamp − Arrived timestamp
Both timestamps have to be captured when they happen, by the tech, at the address. Times typed in at the end of the day are memory, and memory rounds to the nearest half hour.
Across many jobs, the useful numbers are per service type:
Average time on site (service S) = Sum of time on site for S jobs ÷ Number of S jobs
Look at the spread as well as the average. A service that averages 75 minutes but ranges from 40 to 150 needs a different booking rule than one that is always 70 to 80.
Time on site vs wrench time vs drive time
These three get mixed up, and they answer different questions.
| Measure | From | To | Answers |
|---|---|---|---|
| Drive time | Leaving the last job | Arriving | How much of the day is in the truck |
| Time on site | Arrived | Done | How long a job really takes |
| Wrench time | Start of hands-on work | End of hands-on work | How much of the visit is productive work |
Wrench time is always a slice of time on site. The gap between them is diagnosis, customer conversation, waiting for access and parts runs to the truck. That gap is worth watching, but it is real time the job takes, so it belongs in the booking.
How it feeds estimates
Your job duration estimate is a forecast of time on site. If you book a water heater swap at 120 minutes and your recorded time on site for that service averages 155, every water heater day runs 35 minutes late from that job onward.
The fix is to set estimates from recorded time on site, by service, and revisit them every few months. In CrewLink, time on site is recorded when a job is marked done, and future bookings use it. Accurate time on site also makes on-time arrival honest, because the next arrival depends on the last departure; see how to measure on-time arrival.
What to take away
- Time on site = done minus arrived, captured at the address when it happens.
- It is longer than wrench time, and the difference is real job time that belongs in the booking.
- Set duration estimates from recorded time on site by service, and watch the spread, not just the average.
Common questions
Is time on site the same as labor time?
Not exactly. Labor time is often what you bill, and may exclude some on-site minutes or include off-site work. Time on site is simply arrived to done, which is what the schedule needs.
Should time on site include cleanup and payment?
Yes. Anything that keeps the tech at the address keeps them from the next job, so it belongs in the measure and in the estimate.
How many jobs do I need before the average is useful?
There is no fixed rule, but a few dozen jobs of one service type usually gives a stable enough average to book from. Recheck when the mix of work changes.