Utilities · free tool
Calculate days between two dates
Calculate days, weeks and calendar duration between two dates, or add and subtract date units.
- Exact total days
- Calendar years and months
- Weekday count
- Add or subtract dates
Your tool
Date Duration Calculator
Days between two dates
Compare two calendar dates without timezone or daylight-saving surprises.
Add or subtract a duration
Move a date by an exact number of days, weeks, months or years.
Resulting date
Use it well
How to use Date Duration Calculator
Common use cases
- Project deadlines
- Measure an interval or calculate a future milestone from a start date.
- Administrative periods
- Express elapsed time in total days or calendar years, months and days.
- Weekday planning
- Count Monday-to-Friday days while keeping public-holiday limits explicit.
Steps
- Choose a start and end date.
- Read total days, calendar duration, weeks and weekdays.
- Use the second panel to choose a reference date.
- Add or subtract an integer number of days, weeks, months or years.
Limits and good practices
Good practices
- Use total days when exact elapsed time matters.
- Use calendar duration when years and months must remain readable.
- Remember that weekday counts do not exclude public holidays.
- Check month-end results because shorter months clamp the day to their last valid date.
Common mistakes
- Treating weekdays as business days
- The weekday count excludes weekends only; national and company holidays require a dedicated calendar.
- Assuming every month has the same length
- Adding one month to a month-end date uses the final valid day of the destination month.
FAQ
Frequently asked questions
How are days between dates calculated?
The calculator compares civil calendar dates at a timezone-independent day level, so daylight-saving changes do not add or remove hours.
Are both the start and end dates included?
The total is the elapsed interval: equal dates return zero, and consecutive dates return one day.
Does the weekday count exclude public holidays?
No. It counts Monday through Friday and does not apply national, regional or company holiday calendars.
What happens when adding a month to January 31?
The result is clamped to the final valid day of February, preserving a useful calendar-month operation.
Are my inputs sent to a server?
OnSubmit tools run in the browser whenever the task can be processed locally. Avoid pasting production secrets, real banking details or personal data into public tools.