Count the days, weeks and months between two dates, including weekdays only, or add and subtract years, months, weeks and days from a date.
Two everyday questions, both easy to get wrong by hand: how many days lie between two dates, and what date falls a given number of days, weeks, months or years from another. Month lengths and leap years make mental arithmetic unreliable past a couple of weeks.
This page does both. Switch between counting the gap between two dates and adding or subtracting an interval from one.
Enter a start and an end date. You get the gap as a years, months and days breakdown, and as flat totals — days, weeks, months, hours and minutes. It also splits the range into weekdays and weekend days, which is what you usually want for working time.
The 'count the end date as a full day' option decides between the two conventions people mean by 'how many days'. Off, it measures the interval: Monday to Friday is 4 days. On, it counts the days inclusively: Monday to Friday is 5 days. Leave-day and event-length calculations normally want it on; age and duration normally want it off.
Pick a starting date, choose Add or Subtract, and enter any combination of years, months, weeks and days. You get the resulting date, its weekday, its ISO week, and the number of days moved.
Months need a convention because they are not a fixed length, and this is where tools disagree. Here, adding a month keeps the same day number where it exists and clamps to the last day of the month where it does not: 31 January plus one month is 28 February, or 29 February in a leap year. Adding one month to 31 March gives 30 April. This keeps results inside the intended month, which is nearly always what a deadline means.
A consequence worth knowing: this arithmetic is not always reversible. 31 January plus one month is 28 February, but 28 February minus one month is 28 January. Any clamping scheme has this property — it is a property of calendars, not a bug.
A year is a leap year when it is divisible by 4, except centuries, except centuries divisible by 400. So 2024 is a leap year, 2025 is not, 1900 was not, and 2000 was. All of that is handled, including 29 February start dates, which clamp to 28 February in non-leap years.
Both, your choice. By default the result is the interval, so 1 to 8 January is 7 days. Turn on 'count the end date as a full day' for the inclusive count of 8 days, which is what booking and leave calculations usually want.
Weekdays are Monday to Friday and weekend days are Saturday and Sunday, both shown for the range you entered. Public holidays are not deducted, since those vary by country and region.
28 February, or 29 February in a leap year. February has no 31st, so the result clamps to the last day of the target month rather than spilling into March.
Yes, including the century rules — 1900 was not a leap year, 2000 was — and 29 February start dates, which clamp to 28 February in non-leap years.
You can, but the age calculator is built for it and adds the next birthday, the weekday you were born on, and totals in weeks, days and hours.