Man-Hours Calculator
Enter your team size, hours per day, project duration, and wage rate to get total man-hours, productive hours after breaks and efficiency, and a full labor cost breakdown including overtime. Results update as you type.
What are man-hours?
A man-hour (also written as person-hour or labor-hour) is the amount of work one person can complete in one hour working at a standard pace. The unit is additive: if three workers each spend two hours on a task, the total is six man-hours regardless of how those hours are distributed. Project managers use man-hours to estimate cost, schedule workforce requirements, compare bids, and track whether a project is running on time and budget. The term is unit-agnostic: "man" refers to the historical use of the word to mean person, not gender.
The man-hours formula and how this calculator uses it
The core formula is: Man-Hours = Workers x Hours per Day x Days. This calculator extends that foundation in three ways. First, it separates gross man-hours (all scheduled time) from effective hours (scheduled time minus break time) and productive hours (effective hours multiplied by an efficiency factor). This layered view is important because paying for 800 scheduled hours does not mean getting 800 hours of output. Second, it adds overtime: overtime hours are priced at the base rate multiplied by the overtime premium (typically 1.5 for time-and-a-half or 2.0 for double time), and the premium is added on top of the regular-hours cost. Third, cost-per-productive-hour divides total spend by genuine output hours, giving a cleaner efficiency metric than cost-per-scheduled-hour. Formula summary: Total Labor Cost = (Gross Man-Hours x Hourly Rate) + (Overtime Hours x Hourly Rate x Overtime Multiplier).
How to read the efficiency rate
Efficiency rate captures the reality that workers are rarely productive 100% of the time they are on the clock. In office settings, meetings, context switching, and administrative tasks absorb 15-30% of the day. On construction sites, material delays, tool setup, and waiting time typically push efficiency down to 65-80%. Manufacturing lines with tight process control can reach 85-95%. A conservative estimate protects against schedule overruns; an optimistic one causes cost blowouts. If you are unsure, start at 80% and adjust once you have actual productivity data from your team.
Reverse-solving: finding workers needed or hours per person
This calculator solves forward - given workers, hours, and duration, it gives you total cost and hours. To reverse-solve, rearrange the formula manually. If you know you need 1,200 man-hours in 6 weeks with a 5-day week and 8-hour day, you need 1,200 / (6 x 5 x 8) = 5 workers. To find project duration with a fixed team: weeks = Man-Hours / (Workers x Hours per Day x Days per Week). Overtime hours can also absorb unplanned scope: each overtime hour at 1.5x replaces 1.5 hours of regular labor, so 100 overtime hours effectively "buy" 150 hours of regular capacity at the same gross cost.
Typical efficiency rates by project type
| Project / Work Type | Typical Efficiency | Notes |
|---|---|---|
| Office and knowledge work | 70-85% | Meetings, email, context switching reduce output |
| Software development | 75-85% | Higher with strong sprint discipline; lower with interruptions |
| Construction - skilled trades | 80-90% | Well-managed sites with clear sequencing |
| Construction - general labor | 65-80% | Idle time from material delays or weather |
| Manufacturing - assembly line | 85-95% | Process-driven, minimal discretion |
| Healthcare - clinical | 70-80% | Documentation burden reduces direct patient hours |
| Field service / maintenance | 65-75% | Travel and wait time reduce productive share |
| Retail / customer-facing | 75-85% | Varies with foot traffic patterns |
Efficiency (productive hours as a share of effective hours) varies widely by industry and task type. Use these as starting benchmarks.
Frequently asked questions
What is the difference between man-hours and productive hours?
Man-hours (or gross man-hours) is the total scheduled time: workers multiplied by scheduled hours per day multiplied by total days. Productive hours are what you actually get after subtracting break time and applying an efficiency factor. A team of 5 workers scheduled for 8 hours over 10 days generates 400 man-hours, but if each takes a 1-hour break and works at 80% efficiency, productive hours drop to about 280. Quoting productive hours rather than gross hours gives a more honest estimate of deliverable output.
How do I calculate the total cost including overtime?
Total labor cost = (Gross man-hours x base hourly rate) + (Overtime hours x base rate x overtime multiplier). For example, 400 regular hours at $30/hr = $12,000. Adding 20 overtime hours at 1.5x: 20 x $30 x 1.5 = $900. Total = $12,900. This calculator does that arithmetic automatically once you enter the overtime hours and multiplier.
What efficiency rate should I use?
For office and knowledge work, 75-85% is a reasonable default. For construction labor, 65-80% is typical. Highly process-driven manufacturing can reach 85-95%. If you have historical data from previous similar projects, use that figure rather than an industry average, as team-specific factors like experience level, tooling, and management style matter more than the industry category.
How many man-hours are in a work year?
A standard US work year is about 2,080 hours: 52 weeks x 5 days x 8 hours. After subtracting about 10 public holidays and 10 vacation days (160 hours), you get roughly 1,920 available man-hours. Factoring in an 80% efficiency rate gives approximately 1,536 productive man-hours per full-time employee per year.
Can I use this for freelancers or contractors, not just employees?
Yes. The formula is the same whether the workers are employees, contractors, or freelancers. For freelancers you may want to set break time to 0 if they bill only productive time, and adjust the efficiency rate to reflect the actual deliverable pace rather than time on the clock. If different workers have different rates, run separate calculations for each rate tier and add the costs together.
What is cost per productive hour and why does it matter?
Cost per productive hour is total labor cost divided by the number of productive hours. It measures how much you actually pay for real output, not clock time. If your team generates 300 productive hours at a total cost of $12,000, each productive hour costs $40. This metric is useful for comparing projects, evaluating contractor bids, and spotting whether overtime is worth the premium or whether hiring additional workers at the base rate would be cheaper.