Date & Time
Date Difference Calculator
Count the days, weeks, months and working days between any two dates.
Updated 3 Sep 2026
There are 364 days between 1 Jan 2026 and 31 Dec 2026 — 52 weeks, or 260 working days excluding weekends.
Enter a start date and an end date. The calculator returns the total days, weeks, months and years between them, and separately counts the working days excluding weekends.
What is the Date Difference Calculator?
This calculator measures the interval between two dates in several units at once, and separately counts weekdays — which is usually the figure that matters for project deadlines and notice periods.
How to use the Date Difference Calculator
- Enter the start date.
- Enter the end date. If you enter them the wrong way round the calculator swaps them rather than returning a negative.
Formula
Weeks = total days ÷ 7, rounded down
Months = complete calendar months elapsed
Working days = count of days falling Monday to Friday
Working days are counted by stepping through the interval day by day and checking the weekday, which is exact. Public holidays are not deducted, because they vary by country, state and year.
How the calculation works
Calendar differences are computed directly rather than by converting to an average unit, so leap years and month lengths are handled correctly. The weekday count iterates from the start date to the end date and increments only on Monday through Friday.
Worked example
From 1 January 2026 to 21 August 2026:
- Total days: 232
- Weeks: 33
- Complete months: 7
- Working days: 166
Uses and benefits
- Count down accurately to a deadline or event.
- Work out a notice period or contract duration in working days.
- Check how many billable weekdays fall in a period.
Frequently asked questions
No. Working days exclude Saturdays and Sundays only, because public holidays differ by country, state and year. Subtract the holidays that apply to you from the working-day figure.
The calculator swaps them and returns a positive interval, so you get a sensible answer either way.
References
Working days exclude Saturdays and Sundays only. Public holidays vary by jurisdiction and are not deducted — subtract them separately for your location.