Workdays Calculator
Business days between two dates, with weekends counted separately.
What it does
Project plans, notice periods, and shipping promises all count in business days, but calendars show all days. The gap between them decides whether a two week promise means ten working days or fourteen calendar ones.
The tool above walks each date from start to end, tallying weekdays and weekend days separately. The start day counts when it falls on a weekday; the end day stays out as the landing day.
Public holidays stay in the count because they vary by country, state, and company. Subtract your calendar holidays by hand for the plan that survives approval.
UTC date math keeps the count identical worldwide. Local time zones never shift which weekday a date owns at noon UTC.
How to use
- Enter the start date of work.
- Enter the deadline date, which stays uncounted.
- Read workdays for effort math and weekends for checks.
- Subtract public holidays from workdays manually.
Formula
- inclusive start
- Work begins that morning, so it counts.
- exclusive end
- The deadline day itself is delivery, not work.
- UTC weekdays
- Day of week read in UTC so zones never matter.
Payroll weeks and ISO weeks both start Monday, matching this count. Contracts saying inclusive of both ends add one day to the result.
Worked example
Example: 1 Jan to 31 Jan 2026
Start Thursday 1 January, end Saturday 31 January.
- Span: 1 Jan to 30 Jan inclusive is 30 days.
- Four full weeks give 4 x 5 = 20 workdays.
- Leftover Thu 1 and Fri 2 add 2 workdays.
- Total: 22 workdays, 8 weekend days, 30 days.
Reference table
| Span | Calendar days | Workdays |
|---|---|---|
| One week Mon-Sun | 7 | 5 |
| Two weeks | 14 | 10 |
| 30 days | 30 | 20 to 22 |
| 31 days | 31 | 21 to 23 |
| 90 days | 90 | 64 to 66 |
Limits
- Weekends only excluded. Holidays need manual subtraction.
- End exclusive by design. Inclusive contracts add one.
- Shift and part time schedules differ from Mon-Fri.
- Religious and regional weekends vary abroad.
Common mistakes
- Counting both ends and gaining a phantom day.
- Forgetting holidays inside long spans.
- Promising calendar days as workdays.
- Ignoring Friday half days in some regions.
- Using local midnight math across time zones.
Try it yourself
Quick checks. Answers sit tucked under each question.
Workdays Mon 5 Jan to Mon 12 Jan 2026?
Counts 5, 6, 7, 8, 9 January: 5 workdays. The 12th is the landing day.
A 10 workday task starting Mon 5 Jan ends?
Ten weekdays from the 5th land Friday 16 January.
Questions
Does the start day count?
Yes when it is a weekday. The end day stays out as the deadline.
How do I remove holidays?
Subtract weekday holidays inside the span by hand from the workday count.
What about 4 day weeks?
Subtract the weekly off day from results, or count manually for short spans.
Do weekends ever count?
They show separately for checks. Overtime and on call math adds them back deliberately.
Why UTC internally?
So the same dates give the same count in every time zone.
Business days vs workdays?
Same thing here: Monday to Friday minus holidays.