Capacity planning asks how much work can be completed with the people and time available. It does not predict customer demand. A full calendar can still contain an impossible workload if travel, administration or job duration is missing from the estimate.
Use a consistent unit of time
Assume two technicians each have 40 paid hours this week: 80 person-hours. Reserve 16 person-hours for internal work and other non-delivery activity. That leaves 64 delivery person-hours.
Each standard job requires eight person-hours. Two technicians could complete one together in four elapsed hours, but it still consumes eight person-hours.
Unbuffered capacity = 64 ÷ 8 = 8 jobs
This is an hours calculation, not a route plan. Equipment availability, customer access and travel between jobs can impose additional limits.
State the buffer explicitly
Suppose you reserve 20% of delivery time for overruns and disruption:
Planned job hours = 64 × 0.80 = 51.2
Whole jobs that fit = floor(51.2 ÷ 8) = 6
Six jobs use 48 person-hours. The remaining 16 hours of delivery capacity consist of the 12.8-hour buffer and 3.2 hours left by rounding. Do not subtract the buffer again after rounding the job count.
The 20% is an assumed scenario, not a universal staffing recommendation. Choose an allowance using the variability observed in your work.
Test duration before hiring
At ten person-hours per job instead of eight, the same buffered capacity fits five whole jobs. A sixth would need 60 person-hours, above the 51.2 planned threshold, though below the unbuffered 64-hour maximum.
That distinction matters: “physically possible under ideal conditions” is different from “fits the plan with the chosen allowance.” If you routinely consume the buffer, review the estimate rather than treating the buffer as free capacity.
Turn a workload into a gap
Seven eight-hour jobs require 56 person-hours. Compared with the 51.2-hour planning allowance, the gap is 4.8 hours. Compared with total delivery availability, there is no raw shortage. Decide which constraint you are solving before using a staffing calculator.
An overtime decision also needs cost, fatigue, skill and scheduling considerations. This guide calculates time only; it does not prescribe a working-hours policy.
Connect capacity to pricing
A price that assumes 120 billable hours per person will not recover the same costs if practical demand and capacity support only 100. Use labour cost per billable hour alongside this schedule.
Try the HVAC capacity-buffer calculator or staffing-gap calculator, checking each tool’s input convention. For retainers, compare promised monthly hours across all clients using the agency example.
About the examples and sources
The figures are hypothetical teaching examples created for AskToBot, not surveyed prices or recommended industry margins. The linked references explain the underlying concepts; they do not supply or endorse these example figures. The arithmetic is checked against the stated assumptions. This is AI-assisted educational content and has not been independently reviewed by an accountant. Read how we check calculations.
