What does this date calculator do?
This date difference calculator answers two everyday questions. First: how many days (and weeks, months and years) are there between two dates? Second: what date will it be if you add or subtract a number of days, weeks, months or years? It also counts working days (Monday to Friday) — useful for notice periods, project deadlines, delivery estimates, loan tenures and exam countdowns.
How to use it
- Choose Days between dates or Add / subtract.
- Pick your dates from the calendar (the start date defaults to today).
- For a count that includes both the first and last day, tick Include end date.
- In add/subtract mode, enter the number and unit — the result date and weekday update instantly.
How the difference is calculated
Days = End date − Start date (+1 if the end date is included)
The years-months-days breakdown counts complete calendar months, the same way you'd count on a wall calendar. Weekends are Saturdays and Sundays; all other days count as working days.
Example
From 5 October 2026 to 31 December 2026 there are 87 days (88 if you include 31 December) — that's 12 weeks and 3 days, or 2 months and 26 days. Of those 88 calendar days, 64 are weekdays. And 90 days after 5 October 2026 is Sunday, 3 January 2027.
Common uses
- Notice period: add 30, 60 or 90 days to your resignation date.
- Pregnancy & health: count weeks from a date (always confirm with your doctor).
- Finance: find the number of days for an FD or loan — see the FD calculator.
- Age: for your exact age, use the age calculator.