Free tool
Date Calculator: Days Between Dates and Add or Subtract Days
Count the days, weeks and months between two dates, or add and subtract days from a date. Shows weekdays and weekends too. Free and instant.
How to use the Date Calculator
- Choose Days between two dates, or Add or subtract time from a date.
- The start date begins on today. Pick any dates you need.
- For the days between, tick the box if you want both the start and the end date counted.
- Read the days, weeks, months and weekdays, or the resulting date and its day of the week.
How the date calculator works
Days between two dates is the later date minus the earlier date, counted on the calendar. The calculator also shows the same span as weeks and days, as whole years, months and days, and splits it into weekdays (Monday to Friday) and weekend days.
Years, months and days are counted by adding whole months to the earlier date first, then counting the days left over. If the day does not exist in a month (January 31 plus one month), the date moves back to that month's last day, so the result is always a real date.
Worked examples
| From | To | Days | Weeks | Years, months, days |
|---|---|---|---|---|
| Oct 27, 2026 | Jan 5, 2027 | 70 | 10 weeks | 0 years, 2 months, 9 days |
| Jan 1, 2026 | Dec 31, 2026 | 364 | 52 weeks | 0 years, 11 months, 30 days |
| Jan 31, 2026 | Mar 1, 2026 | 29 | 4 weeks, 1 day | 0 years, 1 month, 1 day |
Counting the start day
"Between" usually means the days after the start date through the end date. If you need both ends counted, for example for a hotel stay counted in days of use, tick the box and the count goes up by one. The years, months and days stay the same, because they are measured between the two dates themselves.
Weekdays and business days
Weekdays here are Monday to Friday and do not skip holidays. To count working days around US federal holidays, or to add business days to a date, use the business days calculator.
Other date tools
To see which week of the year a date falls in, use the week number calculator. For someone's age from a date of birth, use the age calculator. Counting down to a day? See the days until Christmas countdown. For time instead of dates, try the hours and minutes calculator.
Frequently asked questions
How many days are there between two dates?
Subtract the earlier date from the later one. From October 27, 2026 to January 5, 2027 is 70 days, which is 10 weeks exactly, or 2 months and 9 days. The start date is not counted unless you tick the box to count both dates.
Does the calculator count the start date?
Not by default. The first day counted is the day after the start date, which is how most people say how many days until or between. Tick Count both the start and end date to add one day.
How do I add 90 days to a date?
Choose Add or subtract time from a date, enter 90 and pick Days. Adding 90 days to October 27, 2026 gives Monday, January 25, 2027.
What happens when I add a month to January 31?
There is no February 31, so the result moves back to the last day of the month. January 31 plus one month is February 28 in a normal year and February 29 in a leap year.
What day of the year is it?
The add mode shows the day of the year, the day of the week and the ISO week number for the date it finds. For any date and for today, the week number calculator also shows the day of the year.