Find the gap between two dates, or add and subtract days, weeks, months and years from a date.
Subtract the earlier date from the later one. 15 January 2024 to 20 March 2026 is 795 days, or 2 years, 2 months and 5 days. To add time, move the years and months first, then the days.
The Date Calculator does two jobs. It measures the time between two dates — as years, months and days, as a total number of days, weeks and hours, and as a count of weekdays — and it adds or subtracts years, months, weeks and days from a start date to give a new date.
People use it for notice periods and probation ends, loan and lease dates, project deadlines, pregnancy and event planning, warranty expiry and legal time limits. Everything runs in your browser. To count days with options such as excluding weekends use the Day Counter; to find which weekday a date falls on use the Day of the Week Calculator.
Dates are converted to whole days at UTC midnight so daylight saving never adds or removes a day, and months are handled with the calendar rather than a fixed 30 days.
| Calculation | Result |
|---|---|
| Days between 15 Jan 2024 and 20 Mar 2026 | 2 years, 2 months, 5 days — 795 days in total |
| Days between 1 Jan and 31 Dec 2026 | 0 years, 11 months, 30 days — 364 days in total |
| 29 Feb 2000 to 28 Feb 2025 | 25 years, 0 months, 0 days |
| 31 Jan 2026 + 1 month | Saturday, 28 February 2026 |
| 15 Mar 2026 + 90 days | Saturday, 13 June 2026 |
| 15 Mar 2026 − 1 year 2 months 1 week 3 days | Sunday, 5 January 2025 |
Months have 28 to 31 days, so “one month later” is not a fixed number of days. Adding one month to 31 January gives 28 February (29 in a leap year). A year has 365 days, or 366 in a leap year — a year divisible by 4 is a leap year, except century years not divisible by 400 (1900 was not; 2000 was).
| Months | Days |
|---|---|
| January, March, May, July, August, October, December | 31 |
| April, June, September, November | 30 |
| February | 28 (29 in a leap year) |
Subtract the earlier date from the later one. Enter both dates in the first calculator to get the exact days, plus the same gap as years, months and days.
Not by default: the count runs from the start date up to the end date. Tick “Include the end date” to count both days, which adds one.
Use the second calculator: choose the start date, select Add, enter the number of days (or weeks, months, years) and press Calculate.
Enter the date, choose Add and type 90 in the Days box. For example, 15 March 2026 plus 90 days is 13 June 2026.
It uses calendar months. If the target month is shorter, the result is clamped to its last day — 31 January plus one month is 28 February (29 in a leap year).
The “Weekdays (Mon–Fri) in the range” row counts Monday to Friday only. It does not know about public holidays.
Divide the total days by 7. The “Weeks and days” row does this for you, for example 795 days is 113 weeks and 4 days.
Yes. Choose Subtract in the add/subtract calculator and enter the years, months, weeks and days to go back.
Years 1 to 9999 in the Gregorian calendar. Dates before 1582 are shown using the same calendar rules projected backwards.
No — it works with calendar dates only, so there are no time-of-day or time zone effects. For clock times across zones use the Time Zone Calculator.
No. All calculations happen in your browser and nothing is uploaded or saved.
