Date Calculator
Days between two dates, add or subtract days from a date, day of the week. Free online date calculator.
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1. Days between two dates
2. Add or subtract time from a date
3. Days until (or since) a date
4. Add or subtract business days
Skips Saturdays and Sundays. Public holidays are not excluded.
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How the date calculator works
This date calculator does the two things people look up most: it counts the days between two dates (also in weeks, months, years and weekdays) and it adds or subtracts days, weeks, months or years from a date to give you the new date and its day of the week. It works with calendar dates, so leap years and month lengths are handled for you.
How the calculation works
- Days between dates: the end date minus the start date. From January 1 to December 25, 2026 is 358 days. Tick “include the end date” if you want to count both the first and the last day (359).
- Adding months: the day of the month is kept when possible. If it does not exist, the last day of that month is used, so January 31 plus one month is February 28 (or 29 in a leap year).
- Weekdays: the count of Monday-to-Friday days, without public holidays.
Examples
| Question | Answer |
|---|---|
| Days from Jan 1 to Dec 25, 2026 | 358 days (51 weeks and 1 day) |
| 90 days after October 14, 2026 | January 12, 2027 |
| 6 months after August 31, 2026 | February 28, 2027 |
| 1 year before March 1, 2027 | March 1, 2026 |
| Days between Oct 14 and Dec 31, 2026 | 78 days |
For deadlines that exclude weekends and holidays, count weekdays and subtract the holidays that apply to you. To see how long remains until a specific day, use days until a date, days from today for 30/60/90-day dates, or days between dates for a dedicated count.
How to use Date Calculator
- Open Date Calculator in RoviDev (you don't need to install anything or register).
- Enter the required data in the tool form.
- Press the button and see the result instantly on the screen.
Date calculator FAQ
How many days are there between two dates?
Subtract the earlier date from the later one. January 1 to December 25, 2026 is 358 days. Tick the include-end-date option to count both the first and last day.
How do I calculate a date 90 days from today?
Choose the start date, select Add and enter 90 days. 90 days after October 14, 2026 is January 12, 2027.
What happens when I add a month to January 31?
The calculator uses the last day of the shorter month, so January 31 plus one month is February 28 (February 29 in a leap year).
Does it count weekends?
The days figure counts every day. A separate line shows weekdays (Monday to Friday) without public holidays.
How many days until a date?
Pick the date in section 3. The calculator counts the days from today, shows the weeks and days, and gives the day of the week. A past date shows how many days ago it was.
How do I add business days to a date?
Use section 4: choose the start date, select Add or Subtract and enter the number of business days. Saturdays and Sundays are skipped; public holidays are not excluded, so add extra days if a holiday falls in the period.
Does it handle leap years?
Yes. The calculation uses the real calendar, including February 29.
Can I subtract time from a date?
Yes. Select Subtract and enter years, months, weeks or days to get the earlier date and its day of the week.