Project Timeline & Labor Hours Estimator
Estimate total labor hours and project duration based on task scope, crew size, daily work hours, and productivity factors.
Formulas Used
Base Labor Hours = Scope of Work ÷ Productivity Rate
Adjusted Labor Hours = Base Labor Hours ÷ Efficiency Factor
Total Labor Hours = Adjusted Labor Hours × (1 + Contingency % ÷ 100)
Crew-Hours per Day = Crew Size × Work Hours per Day
Project Duration (days) = Adjusted Labor Hours ÷ Crew-Hours per Day
Duration with Contingency = Total Labor Hours ÷ Crew-Hours per Day
Assumptions & References
- Productivity rate is expressed in units of work completed per single labor-hour (e.g., sq ft/hr, linear ft/hr).
- Efficiency factor accounts for non-productive time: breaks, setup, coordination, and fatigue. Industry standard ranges from 0.70–0.85 for typical field crews (RS Means, 2023).
- Contingency buffer of 10–15% is standard for well-defined scopes; 20–30% for complex or uncertain projects (PMI PMBOK® Guide, 7th Ed.).
- Project duration is calculated in working days (5-day work week assumed for week conversion).
- This estimator does not account for material lead times, permit delays, weather days, or sequential task dependencies.
- For multi-phase projects, run each phase separately and sum durations, accounting for crew overlap or downtime between phases.
- Reference: Productivity norms from RS Means Building Construction Cost Data and NECA Manual of Labor Units.