Date Calculator
Count the days, weeks, months and business days between two dates, or add or subtract days, weeks, months and years from a date.
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How to use Date Calculator
- 1
Open Date Calculator on this page. It loads right in your browser.
- 2
Add your file, text or values and adjust the settings.
- 3
Copy the result or download it. Nothing is uploaded or stored.
How to use it: Date Calculator
This date calculator has two modes. Days between dates counts the exact number of days from one date to another and also shows the difference in years, months and days, weeks, hours and business days (Monday to Friday).
Add or subtract days moves any date forward or back by years, months, weeks and days (for deadlines, notice periods, warranties or "90 days from today") with an option to count business days only.
How to use it
- Choose Days between dates or Add or subtract days.
- Pick the dates (shortcuts set today, 31 December or Christmas).
- Tick Include the end date if both days should count.
- Read the result: days, years-months-days, weeks and business days, or the new date with its weekday.
How it is calculated
Days are counted using calendar dates, so leap years and month lengths are handled automatically. Business days skip Saturdays and Sundays; public holidays are not removed.
Worked example
From 1 January to 31 December of a non-leap year is 364 days, or 365 counting both days. 90 days after 15 March is 13 June. 10 business days after Friday 3 October 2025 is Friday 17 October 2025.
Who uses it
- Counting down to holidays, birthdays and events
- Deadlines, notice periods and contract terms
- Visa stays and travel planning
- Project planning in working days
Tips
- Check whether your deadline counts the start day: use Include the end date accordingly.
- Business days here exclude weekends only; subtract public holidays yourself.
- Adding a month to 31 January lands on 3 March in non-leap years, because February is shorter: check end-of-month dates.
Free, private and instant: every calculation runs in your browser, nothing is uploaded or stored, and there is no sign-up or limit. Related calculators: age calculator, time calculator, due date calculator.
Features
- Days between two dates
- Years, months and days breakdown
- Business days (Mon to Fri)
- Add or subtract years, months, weeks and days
- Business-day mode for deadlines
Frequently asked questions
How many days are there between two dates?
Enter both dates in Days between dates. Tick Include the end date if you want to count both the first and last day.
How do I add 30 days to a date?
Use Add or subtract days, pick the start date and type 30 in Days. The result shows the date and weekday.
How do I count business days?
The result in Days between dates includes business days (Monday to Friday). For deadlines, tick the business-day option in Add or subtract.
Are leap years taken into account?
Yes, the calculator uses real calendar dates, so 29 February is counted in leap years.
How many weeks until a date?
The Weeks field shows full weeks and leftover days, e.g. 100 days = 14 weeks 2 days.
Is this calculator free and private?
Yes. It is completely free, needs no account and runs entirely in your browser, so the numbers you type are never sent to a server or stored.