Date difference

Days, weeks, months and working days between two dates

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What is Date difference?

This tool counts how many days there are between two dates and breaks it down into years, months and days. It also tells you how many are business days (Monday to Friday), and how many weeks, hours or minutes.

You can also add or subtract days, business days, weeks, months or years from a date to find out when a deadline, warranty or contract expires.

How to use it

  1. Choose the “From” and “To” dates, or use “From today” and “Until today”.
  2. Turn on “Include end date” if you want to count both ends.
  3. Check the total number of days and the breakdown into business days, weeks, months and years.
  4. To calculate a deadline, go to “Add or subtract from a date”, enter the amount and choose the unit.
  5. Click “Use as date” to chain another calculation from the result.

Advantages

Technical details

Dates are treated as calendar days in UTC, without times, to avoid offsets caused by daylight saving time changes. The difference in days is (end − start) / 86,400,000 ms, and the breakdown into full years, months and days is calculated by subtracting components and borrowing from the previous month. Business days are Monday to Friday: full weeks × 5 are counted and the remaining days are checked one by one; national, regional and local public holidays are not deducted. Years are shown by dividing by 365.2425 (average Gregorian year). When adding months or years, if the day doesn't exist in the target month, the last day of that month is used. Adding business days skips Saturdays and Sundays (up to 100,000 days).

Frequently asked questions

How do I calculate the number of days between two dates?

Choose both dates and the tool gives you the total number of days, plus the breakdown into years, months and days, weeks and hours.

Are public holidays counted as business days?

Business days are counted Monday to Friday and public holidays are not deducted, because they vary by region and municipality. Subtract them manually if there are any.

Are the first and last days included?

By default, the difference between the dates is counted. If you turn on “Include end date”, both ends are counted, as in a contract from the 1st to the 31st that lasts 31 days.

What date will it be in 90 days?

In “Add or subtract from a date”, keep today's date, enter 90, choose “Days” and you'll see the date with its day of the week.

What happens if I add one month to January 31?

The result is the last day of February (28, or 29 in a leap year), because February 31 doesn't exist.

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