Date Difference Calculator - Days Between Dates
Calculate the calendar span between two dates in days, weeks, months, or years, with an option to include the end date.
How the Date Difference Calculator Works
Compare any two calendar dates and see the elapsed interval expressed independently as complete days, weeks, months, and years.
Use the optional inclusive setting when both the start date and end date should count toward a booking, event, leave period, or other date range.
Pick a start and an end date to see the span as complete days, weeks, months, and years, each measured independently rather than as remainders of one another. A combined weeks-and-days figure is shown for spans that read more naturally that way.
Both endpoints are treated as calendar dates with no time of day, so a span crossing a daylight-saving change still counts whole days. Month and year figures count completed units: a 40-day span reports one month, not one month and ten days.
Worked examples: From 1 January 2026 to 31 December 2026 is 364 days (365 if you count both the start and end date) — From 1 March 2026 to 1 April 2026 is 31 days. From 10 October 2026 to 25 December 2026 is 76 days — From 1 January 2024 to 1 January 2026 is 731 days, because 2024 is a leap year with 366 days.
Frequently Asked Questions
- Does this include the end date?
- By default, the end date is excluded (meaning the difference between today and tomorrow is 1 day). You can toggle the "Include end date" checkbox to add 1 day to the result.
- Is it accurate for leap years?
- Yes, the calculation uses a robust date library that correctly handles leap years and variable month lengths.
- Can the end date be earlier than the start date?
- Yes. The calculator uses the absolute difference, so swapping the start and end dates produces the same positive duration.
- Why does the month result not equal days divided by 30?
- Calendar months have different lengths. The month result counts complete calendar-month periods between the selected dates instead of treating every month as 30 days.
- What is the difference between this and the time-between-dates calculator?
- This calculator compares date-only values and focuses on calendar days, weeks, months, and years. Use Time Between Two Dates when the hours, minutes, and seconds of each timestamp matter.
- How many days are there between two dates?
- Subtract the earlier date from the later one. From 1 January 2026 to 31 December 2026 is 364 days, or 365 days if you include both dates.
- How many weeks are between two dates?
- Divide the day count by 7. For example, 76 days from 10 October 2026 to 25 December 2026 is 10 weeks and 6 days.