Project Schedule Calculator

About the Project Schedule Calculator

Estimates a project's calendar duration from the total work effort (person-days), the number of people working and their productivity.

How to use this calculator

1. Enter the total amount of work for the project, such as tasks, hours, or deliverables.
2. Enter the number of resources available, such as workers or machines.
3. Add the productivity rate if the calculator asks for how much one resource can complete in a given time.
4. Click calculate to estimate the project duration.
5. Review the result and adjust tasks or resources if the timeline is too long.

The formula explained

The basic idea is to compute duration from total work divided by the total work completed per unit of time. In a simple setup, this can be written as \(\text{duration} = \frac{\text{total work}}{\text{resources} \times \text{rate}}\).

• \(\text{duration}\) = the estimated project length in time units
• \(\text{total work}\) = the total amount of work that must be completed
• \(\text{resources}\) = the number of people, machines, or teams working
• \(\text{rate}\) = how much one resource completes per time unit

Step by step method

1. Find the total amount of work that needs to be finished.
2. Determine how many resources are available and how fast each one works.
3. Divide the total work by the combined work rate to estimate the duration.

Worked example

Problem. A team must complete \(120\) tasks. There are \(4\) workers, and each worker completes \(6\) tasks per day. How long will the project take?

1. Compute the combined daily rate: \(4 \times 6 = 24\) tasks per day.
2. Divide total work by the combined rate: \(120 \div 24 = 5\) days.
3. So the estimated project duration is \(5\) days.

Tips and common mistakes

• Make sure your work units and time units match, because mixing tasks, hours, and days can give a wrong result.
• If the calculator includes nonworking time, such as weekends or setup delays, include that separately so the estimate is realistic.

Frequently asked questions