Days Between Dates Calculator
Pick a start date and an end date to instantly find the number of days between them. Toggle whether both endpoints are counted, and see week, month, and year approximations at the same time.
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Input
Result
Please enter a start date and an end date.
How it works
- Select a start date and an end date from the calendar, and the number of days between them is shown automatically.
- Turn on "count both endpoints" to count the start and end dates as one day each, which increases the total by one day. Switch it according to how you want the period counted.
- Besides the day count, you can also see approximate weeks, months, and years along with a years-months-days breakdown.
- The end date must be the same as or later than the start date. A message appears if the order is reversed.
- The calculation accounts for leap years and the differing number of days in each month, so it works well for checking contract periods or the days remaining until an anniversary.
- You can share the result directly to X (formerly Twitter) to easily post the period you calculated.
Worked example: April 1 to September 30
Enter April 1, 2026 as the start date and September 30, 2026 as the end date and the result is 182 days. You can check it month by month: 29 days left in April (the 2nd through the 30th), then 31 for May, 30 for June, 31 for July, 31 for August and 30 for September. 29 + 31 + 30 + 31 + 31 + 30 = 182. The start date itself is not counted; you add up every day after it, through the end date.
Switch on the option to count both endpoints and the total becomes 183, which is the right figure if you want the number of calendar days in that half-year, April 1 and September 30 included. The years-months-days line is always based on the plain difference, so it reads 5 months 29 days with the option on or off.
Which counting method do you need?
The same pair of dates can give two answers that differ by one, and both are correct for different questions. A simple test: are you counting the gaps between days (nights, elapsed time, days remaining) or the days themselves (how many days something happens on)?
- Hotel stays: check in on July 10, check out on July 13, and the plain difference gives 3 nights. Counting both endpoints gives 4, the number of calendar days you are there.
- Countdowns: from October 23, 2026 to December 25, 2026 the difference is 63 days. Countdowns normally use the plain difference.
- Events and courses: a workshop running from the 5th to the 9th takes place on 5 days, so include both endpoints.
- Daily rates and prorating: if a rental or subscription is active on both its first and last day, the inclusive count is usually the one to multiply by. Check what the contract says.
- Age in days and time served: elapsed-time questions use the plain difference.
Month-end and leap-year traps
Months are not a fixed length, so month counts can surprise you. From January 31, 2026 to February 28, 2026 is 28 days, and the breakdown shows it as 1 month 0 days. January 28 to February 28 is 31 days, yet it also shows 1 month 0 days. February has no 31st, so a month after January 31 is pinned to the last day of February. Treat the month figures as a convenient summary and compare periods by days when precision matters.
Years vary too. March 1, 2026 to March 1, 2027 is 365 days, but March 1, 2027 to March 1, 2028 is 366, because February 29, 2028 falls inside it. If a contract or warranty is written in days rather than years, a leap day can move the end date by one.
Getting more from the result
The approximate weeks figure is the plain difference divided by 7 and rounded to one decimal. From October 23, 2026 to January 1, 2027 is 70 days, which is exactly 10.0 weeks. That makes it easy to plan biweekly or weekly cycles. The hours figure is the displayed day count multiplied by 24, so it gains 24 hours when you count both endpoints.
A shared link includes the start and end dates, so you can come back to the same period later or send it to someone else. The endpoint setting is not part of the link, so mention which method you used when you share it to avoid an off-by-one disagreement.
Frequently asked questions
- How is the number of days between two dates counted?
- Pick a start date and an end date from the calendar and the days between them are shown automatically. Leap years and the varying length of each month are accounted for, so it works for contract periods or counting down to an anniversary.
- What does the include-both-endpoints option do?
- Turning it on counts both the start and end dates as full days, which adds one to the total. For example, from the 1st to the 3rd is 2 days when off and 3 days when on, so switch it to match how you count a period.
- How is this different from adding days to a date?
- This tool measures the span between two fixed dates. If you instead want the date that falls a certain number of days before or after a reference date, use the add-days tool. Note the end date must be the same as or later than the start date.
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