How to Estimate Crew Productivity and Duration
Quick answer
Estimate duration from the whole crew’s output per productive hour: productive hours = quantity ÷ crew output rate. Divide by productive hours per day for crew days. Multiply crew days by people and paid hours per day to estimate paid person-hours. Keep the unit consistent throughout.
Choose a measurable unit of work
A drainlaying crew might measure metres of a defined pipe installation; a concrete crew might measure square metres of a defined slab activity. Define what the rate includes before reusing it. Excavation alone is different from excavation, bedding, laying, testing and backfill.
- —Record quantity and unit: metres, m², m³ or items.
- —Use output for the whole crew, not a per-person rate, in this calculation.
- —Use comparable completed work to estimate the output rate.
- —Split changing ground, access or installation details into separate activities.
Distinguish productive time from paid time
Paid hours include time that may not produce measured output: setup, travel, briefings, waiting and pack-down. Use a realistic productive-hours allowance for the activity and keep paid person-hours visible. Do not add the same downtime twice if your historic daily rate already includes it.
Formulas
Productive crew-hours = quantity ÷ output per productive crew-hour
Crew days = productive crew-hours ÷ productive hours per day
Paid person-hours = crew days × people in crew × paid hours per day
Worked example: a defined drainage activity
These are illustrative inputs, not an industry production benchmark. A different trench detail, ground condition or crew setup can change the rate substantially.
Worked example
Quantity: 120 m. Assumed output: 4 m per productive crew-hour.
Crew size: 3 people. Paid day: 8 hours. Productive time: 6 hours/day.
Productive crew-hours = 120 ÷ 4 = 30 hours.
Crew days = 30 ÷ 6 = 5 days.
Paid person-hours = 5 × 3 × 8 = 120 hours.
Check sensitivity before promising a finish date
At 3 m per productive crew-hour, the same quantity takes 40 productive crew-hours and about 6.67 crew days. At 5 m per hour it takes 24 productive crew-hours and 4 days. Comparing scenarios makes the assumptions visible.
- —Check material availability and plant support.
- —Identify inspections, access windows and other dependencies separately.
- —Convert crew days into an actual work calendar before setting dates.
- —Compare completed quantity and recorded hours daily; update the remaining-work estimate when conditions change.
Use an estimate to plan the work, then compare allocations and recorded hours as the job progresses in Fieldlink.
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