Man-Hours Calculator
Print Report| Man-Days Equivalent | 0 Man-Days |
| Daily Team Labor Capacity | 0 hrs / day |
Whether you are a construction contractor bidding on a new build or a software project manager planning a sprint, accurately estimating labor is the difference between a profitable project and a massive financial loss. To price your projects correctly, you need to know exactly how much human effort is required.
Our free Man-Hours Calculator allows you to instantly determine the total amount of uninterrupted labor required to complete a task. By multiplying your team size by their daily hours and total working days, you can confidently build project budgets and timelines.
How to Calculate Man-Hours (Person-Hours)
A “man-hour” (increasingly referred to as a “person-hour”) represents the amount of work completed by one average worker in one hour of uninterrupted time. The formula to calculate the total man-hours for a project is simple multiplication.
The Man-Hours Formula:
Total Man-Hours = Number of Workers × Hours Worked per Day × Number of Days
Step-by-Step Example Calculation
Imagine you run a landscaping company and you are bidding on a large commercial park project. You plan to assign a crew to the job for a full workweek.
- Number of Workers: 5 landscapers
- Hours Worked per Day: 8 hours (standard shift)
- Number of Days: 5 days (Monday through Friday)
Let’s plug these numbers into the formula:
Total Man-Hours = 5 × 8 × 5
Total Man-Hours = 200
This project will require exactly 200 man-hours to complete. If your average fully burdened labor cost is $30 per hour, you now know that your baseline labor budget for this project must be at least $6,000 (200 hours × $30).
The Danger of Man-Hours: The Mythical Man-Month
While calculating man-hours is essential for budgeting, project managers must beware of a famous software engineering trap known as Brooks’s Law (often called the Mythical Man-Month).
The trap assumes that men and months are perfectly interchangeable. Mathematically, a 100-hour project can be completed by 1 person in 100 hours, or 100 people in 1 hour. In reality, this is false.
- Communication Overhead: Adding more workers to a project increases the time required for training, meetings, and coordination.
- Sequential Tasks: Some tasks cannot be divided. As the famous saying goes: “Nine women cannot make a baby in one month.”
When using this calculator to compress a timeline, remember that doubling your team size will rarely cut the project timeline exactly in half.
Frequently Asked Questions (FAQ)
What is the difference between Man-Hours and Duration?
Duration is the strict calendar time it takes to finish a project (e.g., 3 weeks). Man-Hours is the actual human effort required during that duration (e.g., 120 hours of labor). A project might have a duration of an entire month, but only require 10 man-hours of actual work.
Should I include lunch breaks in my calculation?
No. A man-hour measures uninterrupted, productive work. If your employees are on site for 9 hours but take a 1-hour unpaid lunch break, you should only calculate 8 hours of productive time per worker.
Is “Person-Hours” the same thing?
Yes. “Person-hours” or “labor-hours” are the modern, gender-neutral terms for the exact same metric. The mathematical formula and application are completely identical.