Calculator Inputs
Example Data Table
| Scenario | Quantity | Crew | Rate (per worker) | Total time | Workdays | Finish | Estimated cost |
|---|---|---|---|---|---|---|---|
| Interior painting touch-up | 1200 sq ft | 3 | 18 sq ft/h | 28h 30m | 4 | 2026-02-07 12:30 | 1,197.00 |
| Concrete surface prep | 320 sq m | 5 | 4.2 sq m/h | 23h 30m | 3 | 2026-02-06 13:00 | 1,880.00 |
| Fixture installation | 48 fixtures | 2 | 1.1 fixtures/h | 26h 00m | 4 | 2026-02-09 11:00 | 936.00 |
| Material hauling | 22 loads | 3 | 0.55 loads/h | 19h 00m | 2 | 2026-02-05 15:00 | 741.00 |
Formula Used
How to Use This Calculator
- Enter the work quantity and select the correct unit type.
- Add your production rate per worker using recent field data.
- Set crew size and adjust efficiency for site constraints.
- Include fixed time for mobilization, access, setup, and cleanup.
- Apply breaks and contingency to reflect realistic delivery.
- Choose shift hours, workdays per week, and a start date to estimate finish.
- Click Calculate, then export CSV or PDF for sharing.
Production Rate Benchmarks for Common Services
Field rates vary by access, finish requirements, and congestion. Light interior painting often ranges from 15–25 sq ft per hour per worker, while detailed trim can drop below 10. Surface preparation on concrete frequently lands near 3–6 sq m per hour depending on tooling and dust control. Fixture installs may average 0.8–1.5 fixtures per hour once materials are staged. Linear tasks like conduit pulling can reach 20–45 linear ft per hour when routing is clear.
Crew Efficiency Drivers on Active Sites
Efficiency reflects how much of your planned production is truly achieved. A well-coordinated crew with clear work fronts may sustain 90–105% when rehandling is minimal. Mixed trades, limited laydown space, and long travel paths can pull efficiency toward 70–85%. Use the factor to represent coordination losses, safety briefings, permits, and intermittent stoppages. Capture lift waits, tool sharing, and inspection holds here instead of inflating the base rate.
Allowances for Breaks, Access, and Rework
Breaks and minor delays are best applied to variable work time because they scale with scope. Many supervisors start with 8–12% for breaks, tool changes, and short waits. Contingency is added after fixed time to protect milestones against uncertainty such as late material delivery, weather exposure, and quality rework; 3–7% is common for controlled interior work. For weather-exposed scopes, 8–12% contingency is often more realistic.
Translating Hours into Workdays and Finish Dates
Once total hours are rounded, divide by shift hours to estimate workdays. For example, 26.5 total hours on an 8-hour shift becomes 4 workdays. If your pattern is six working days per week starting Monday, the finish date advances through workdays and skips the off-day automatically. Adjust week start if your crews run Sunday-first schedules. Longer shifts reduce calendar days but can increase fatigue.
Using Crew-Hours for Budget and Resource Planning
Crew-hours equal total hours multiplied by crew size, a practical metric for staffing and cost. A 4-person crew completing 26.5 hours represents 106 crew-hours. If labor is 15 per worker-hour, the labor portion estimates to 1,590. Use exports to compare scenarios, align subcontractors, and document assumptions for client communication. Pair crew-hours with daily targets to track progress and trigger early corrective action.
FAQs
What efficiency factor should I start with?
Start around 85–95% for organized interior work and 70–85% for congested, multi-trade areas. Refine it using recent daily outputs from similar projects and the same crew composition.
Should breaks be a percentage or fixed hours?
Use a percentage for routine breaks and short interruptions that scale with scope. Use fixed hours for mobilization, permits, long travel, or one-time setup tasks that occur regardless of quantity.
How do I choose a production rate per worker?
Use measured outputs from timecards or daily reports on comparable work. If no history exists, begin with conservative benchmark ranges, then adjust after a short pilot run and update the estimate.
Why does rounding change my finish date?
Rounding aligns estimates with practical scheduling blocks. When rounded hours cross a shift boundary, the calculated workdays can increase by one, which shifts the finish date accordingly.
How do workdays per week affect the schedule?
Fewer workdays per week introduce more non-working days, extending the finish date even if total hours stay the same. Seven-day schedules compress the calendar but may increase fatigue and risk.
Can I use this for subcontractor comparisons?
Yes. Enter each subcontractor’s rate, crew size, and allowances to compare total hours, workdays, and cost. Keep units consistent and document assumptions so bids are evaluated on the same basis.