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Days Between Dates Calculator

Choose a start date and an end date. The calculator shows the elapsed count (the simple difference between the two dates), the inclusive count that also counts the end date, the span in weeks and days, and the calendar distance in years, months and days.

Every calculation runs in your browser. The dates, times and hours you enter are never sent to a server, saved to a cookie or stored in your browser.

Calculate

Dates to compare

When this is on, the start date and the end date both count as days.

Result

Choose a start date and an end date, then select Calculate.

When this count is useful

Planning a deadline

A project starts on 3 March and has to be delivered by 30 April. The elapsed count says exactly how many days that leaves, so a schedule can be built on days rather than on guesses about month lengths.

Checking a notice or cancellation period

A contract says "30 days". Enter the day the notice starts and the day it must end: the elapsed count shows whether the period really covers 30 days or ends a few days short.

Measuring an event or trip

For a holiday, a warranty or a school break, people usually mean both the first and the last day. Switch on the inclusive count to get that number instead of the difference.

Counting an age in days

Enter a birth date as the start and today as the end to see the exact number of elapsed days, plus the calendar breakdown in years, months and days.

Counting rules and edge cases

  • The elapsed count is end minus start: 1 January to 2 January is one day, and the same date returns zero.
  • The inclusive count adds one day so that both the first and the last date count, which is the convention calendars use for events and trips.
  • Dates are calendar dates, not timestamps. Time zones, daylight-saving changes and the local clock cannot move the result.
  • Leap years follow the Gregorian rule: 29 February exists in 2024 and 2028, but not in 2023 or 2100.
  • If the end date is earlier than the start date, the two dates keep the order you entered: the elapsed count is shown as a positive magnitude and a direction line explains whether the end date is before or after the start date.
  • The calendar difference is counted in real years and months, not by dividing the total number of days by 365 or by an average month length.

How the calculator counts

Each date is first converted to a whole-day index on the proleptic Gregorian calendar, which makes the elapsed count a single subtraction. The inclusive count adds one to that subtraction, weeks and days come from dividing the elapsed total by seven, and the calendar breakdown walks the years and months between the two dates, borrowing days from the previous month where a calendar count would do the same by hand.

Limits and caveats

  • The inputs are calendar dates only. A deadline that matters at a particular time of day cannot be checked here.
  • Only the Gregorian calendar is modelled; earlier historical calendars are not supported.
  • Holidays, weekends and working-day conventions are not known to the calculator. Subtract non-working days yourself or use a working-calendar tool if that is what you need.
  • The result is a number of calendar days, not a duration between two points in time.

Privacy and your data

The calculation happens in your browser with plain JavaScript. The two dates you enter are not posted to a server, written to a cookie or kept in local storage, and no account or profile is involved.

These utilities are informational tools, not legal, payroll or tax advice. Check your contract or the rules that apply to you before relying on a result for a binding decision.

Frequently asked questions

Does the calculator count both dates?
By default no: the elapsed count excludes the start date and includes the end date, so 1 January to 2 January is one day. Turn on the inclusive option if you want both endpoints counted.
How do I count the days from today to a future date?
Put today as the start date and the future date as the end date. The elapsed count is the number of days from today; the inclusive count treats today as day one.
What happens if the end date is before the start date?
You still get a result: the dates keep the order you entered, the elapsed count is shown as a positive magnitude, and the direction line tells you that the end date is before the start date.
Does it handle leap years and month ends?
Yes. 29 February is counted correctly in every leap year, and month-end spans such as 31 January to 28 February are counted as real calendar months and days.

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