Enter the estimated effort in hours, your team size and how many productive hours each person works per day. The calculator counts forward over real work days, skipping weekends, US federal holidays and your own days off, and shows the finish date on a calendar.
Last updated:
Work days
Estimated completion date–
Work-day calendar
Work dayWeekend / non-work dayHoliday or day offStart / finishDeadline
Everything is calculated in your browser. US federal holidays are generated for any year using the official rules, with Saturday holidays observed on the Friday before and Sunday holidays on the Monday after.
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How to use the Project End Date Calculator
Pick the start date and choose whether work begins on that day or the next work day.
Enter the total effort in hours, the number of people and their productive hours per day; add a buffer if you want contingency.
Set the work week by toggling the day buttons and decide whether to skip US federal holidays.
Add extra days off such as vacations or a year-end shutdown, one date or date range per line.
Read the completion date, then check the calendar, compare it with an optional deadline and copy or download the schedule.
The formula behind the end date
The calculator turns effort (person-hours of work) into duration (elapsed calendar time) in three steps:
Work days needed = planned effort ÷ (team size × productive hours per person per day), rounded up to a whole day.
End date = the date reached after counting that many work days forward from the start, skipping non-work weekdays, holidays and your days off.
Worked example: a 480-hour project starts on Monday, January 4, 2027 with 3 people working 6 productive hours a day. Daily capacity is 3 × 6 = 18 hours, so 480 ÷ 18 = 26.67, which rounds up to 27 work days. Counting Monday to Friday and skipping Martin Luther King Jr. Day (January 18), the 27th work day is Wednesday, February 10, 2027, 38 calendar days after the start. Add a 20% buffer (576 hours, 32 work days) and Washington's Birthday on February 15 also falls inside the schedule, moving the finish to Thursday, February 18, 2027.
Quick reference: work days by effort and team size
Work days needed at 6 productive hours per person per day, rounded up. Divide by 5 for an approximate number of weeks on a Monday–Friday schedule (before holidays).
Effort (hours)
1 person
2 people
3 people
5 people
8 people
40
7
4
3
2
1
80
14
7
5
3
2
160
27
14
9
6
4
320
54
27
18
11
7
480
80
40
27
16
10
1,000
167
84
56
34
21
2,000
334
167
112
67
42
Tips for a more realistic finish date
Use focus hours, not paid hours. An 8-hour day rarely contains 8 hours of project work. If your team splits time across projects, enter only the share spent on this one (for example 3 hours for someone on the project half-time).
Count part-time people as fractions. Team size accepts decimals, so two full-time developers plus one person at 50% is 2.5.
Block out known absences. Add vacations, training days and holiday shutdowns as ranges such as 2026-12-28 to 2026-12-31; they are skipped like public holidays.
Add a buffer for uncertainty. Estimates for new or poorly defined work tend to be optimistic. A contingency of 10–30% is common; record it separately so you can see how much of the schedule is protection.
Watch dependencies. The calculation assumes work can be shared evenly. If some tasks must wait for others, break the project into phases, calculate each phase and start the next one from the previous end date.
Check against the deadline. Enter a target date to see slack or delay and the team size, daily hours or scope cut that would close the gap.
Frequently asked questions
How do you calculate a project end date from effort hours?
Divide the total effort in hours by the team's daily capacity (number of people × productive hours per person per day) and round up to get the number of work days. Then count that many work days forward from the start date, skipping weekends, holidays and planned days off. The day the last work day lands on is the estimated end date.
What is the difference between effort and duration?
Effort is the total amount of work, measured in person-hours (or person-days). Duration is the elapsed calendar time to finish it. A 480-hour task done by three people working 6 productive hours a day takes 480 ÷ 18 = 26.7, so 27 work days, which is more than five calendar weeks once weekends are included.
How many productive hours per day should I use?
Few people spend all 8 paid hours on project work: meetings, email, support and breaks take a share. Many planners use about 5 to 6.5 focused hours per person per day. If you track time, use your team's real average; otherwise start with 6 and add a contingency buffer.
Does adding more people always finish the project sooner?
Only in this simple model. The calculator assumes work can be split evenly, so doubling the team halves the duration. In practice new people need onboarding, communication overhead grows and some tasks must happen in sequence, so the real gain is usually smaller. Treat the result as an estimate, not a promise.
Which holidays are skipped?
When the option is on, the 11 US federal holidays are skipped: New Year's Day, Martin Luther King Jr. Day, Washington's Birthday, Memorial Day, Juneteenth (from 2021), Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving and Christmas. A holiday on Saturday is observed the Friday before and one on Sunday the Monday after. You can add company holidays or vacations as extra days off.
How much contingency buffer should I add?
It depends on how well understood the work is. Familiar, well-specified work might need 10%, while new or uncertain work often gets 20% to 30% or more. The buffer is added to the effort before the end date is calculated, so a 20% buffer on 480 hours plans for 576 hours.
Can I count weekends or a four-day week?
Yes. Toggle the day buttons to define your work week. Turn Saturday on for a six-day week, or turn Friday off for a Monday-to-Thursday schedule. Only the highlighted days receive hours.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.