How to use this calculator
- Enter the project quantity and operating assumptions.
- Use measured project rates where available.
- Select Calculate to update the result and supporting metrics.
- Change one input at a time to compare scenarios.
#2212 · Real Estate & Construction Tool
Structural Steel Project Duration Calculator
Estimate the working days and calendar weeks needed to erect a planned steel tonnage. The calculator combines crew output, number of crews, working days per week, and a schedule contingency without embedding a fixed productivity assumption.
Calculator
Project inputsFormula
Planned days = [tons ÷ (crew-day rate × crews)] × (1 + contingency %)
What the result means
Working days count only scheduled erection days. Calendar weeks translate that duration using the workdays-per-week input, so weekends or other nonworking days are not silently treated as production days.
Parallel crews are assumed not to constrain one another. Check crane, laydown, access, and supervision limits before relying on the result.
Example calculation
For 600 tons, two crews producing 12 tons per crew-day need 25 base working days. With 10% contingency, the plan becomes 27.5 working days, or 5.5 weeks on a five-day schedule.
Tips for better results
- Use a production rate from a comparable steel package.
- Model alternate crew counts before committing resources.
- Add explicit holidays outside this simple workweek conversion.
- Review whether multiple crews truly have independent work fronts.
Frequently asked questions
Does this calculate a finish date?
No. It calculates duration; apply the result to a project calendar that contains the actual start date and holidays.
What is a crew-day?
One crew-day is one planned shift for one complete erection crew.
Should weather be included in contingency?
It may be included if the percentage reflects a documented weather allowance rather than an arbitrary markup.
Can the calculator model weekend work?
Yes. Set workdays per week to six or seven if those days are genuinely planned.
Why does adding crews shorten duration linearly?
The formula assumes each crew maintains the same output without sharing constraints; real projects may scale less efficiently.
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Inputs and units
| Variable | Unit | Use |
|---|---|---|
| Quantity | tons | Remaining erection scope |
| Production capacity | tons/crew-day × crews | Combined daily output |
| Contingency | percent | Added working time |