Project Duration Calculator

How to calculate project duration?

Project duration is the measure of time from the start to the end of a project. To calculate it manually, you determine the total effort required in hours and divide it by your team's daily capacity or availability.

Completion = Start Date + (Total Hours / Daily Hours)

Using the duration calculator: an example

To illustrate how this works, let's look at a typical software development sprint or small project estimated at 120 total work hours.

Step-by-step calculation:

1. Identify Total Hours: 120 hours of work.
2. Identify Daily Capacity: 8 hours per day (1 full-time person).
3. Divide Hours by Capacity: 120 / 8 = 15 working days.
4. Account for Weekends: 15 working days equals approximately 3 full calendar weeks.

Frequently Asked Questions

Does this include weekends?

Standard duration formulas calculate 'working days'. To find the actual calendar completion date, you must skip over Saturdays, Sundays, and any regional public holidays.

What if my daily hours vary?

If you work part-time or have varying availability (e.g., 4 hours on Friday), it is best to use an average 'hours per day' figure for a rough estimate, or map specific hours to a project calendar for precision.

How do I handle project delays?

Experienced project managers always include a 'buffer' or 'contingency' time. Adding 20% to your total hours estimation is a common strategy to protect against unforeseen technical challenges or scope changes.