📆 Date Difference Calculator
Find exactly how many days, weeks, months and years separate two dates, including the number of weekdays in between.
Quick answer: Subtract the earlier date from the later one. From January 1, 2024 to December 31, 2024 is 365 days (52 weeks and 1 day), of which 261 are weekdays – or 366 days if you include the end date.
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Date Difference Calculator inputs
Result
From Thursday, January 1, 2026 to Sunday, October 11, 2026
283 days
End date not included
| Years, months, days | 9 months and 10 days |
| Months and days | 9 months and 10 days |
| Weeks and days | 40 weeks and 3 days |
| Total days | 283 |
- Business days (Mon–Fri)
- 202
- Weekend days
- 81
- Hours
- 6,792
- Minutes
- 407,520
How to count the days between two dates
Convert each date to a running day number (days since a fixed starting point) and subtract. This avoids having to count month lengths by hand and automatically accounts for leap days.
Days = day number(end) − day number(start) (+1 if the end date is included)
Weeks are the total divided by 7 with the remainder shown as days. Months and years are counted on the calendar: step forward whole months from the start date, then count the days left over.
Worked example
January 1, 2024 → December 31, 2024: 2024 is a leap year with 366 days, and the gap between its first and last day is 365 days, or 52 weeks and 1 day. Measured on the calendar that is 11 months and 30 days. The year started on a Monday, so 261 of those days are Monday–Friday. Tick "include the end date" and the answer becomes 366 days, or exactly 1 year.
Days in each month
| Months | Days |
|---|---|
| January, March, May, July, August, October, December | 31 |
| April, June, September, November | 30 |
| February | 28 (29 in a leap year) |
Tips
- Deadlines: "within 30 days" usually means the gap, not counting the start day – check the wording of your contract.
- Durations of events: a festival running Friday to Sunday lasts 3 days, so include the end date.
- Order doesn't matter: if the end date is earlier than the start, the dates are swapped and the result is the same.
- Working days: for a count that excludes holidays, use the business days figure and subtract your public holidays.
Frequently asked questions
Does the calculator include the end date?
Not by default: like most date maths it counts the gap, so Monday to Tuesday is 1 day. Choose "Yes" to count both the start and end dates, which adds one day – useful for hotel nights versus calendar days or event durations.
How are leap years handled?
Every calculation uses the Gregorian calendar, so February 29 is counted in leap years (years divisible by 4, except century years not divisible by 400). 2024 has 366 days; 2100 will have 365.
How are months counted when they have different lengths?
Whole months are counted from the start date to the same day number in a later month. If that day does not exist, the last day of the month is used, so January 31 plus one month is February 28 (or 29).
Are public holidays excluded from business days?
No. Business days here are simply Monday to Friday. Subtract any public holidays that fall on weekdays in your country to get the final working-day count.