How are months calculated in date differences?

Calendar months are used, not 30-day intervals. The difference from January 31 to March 31 is exactly 2 months, even though February has 28 or 29 days.

What is a business day?

A business day (working day) is any weekday (Monday–Friday) that is not a public holiday. This calculator counts calendar days; for business days, you'll need to account for public holidays manually.

How do I calculate someone's age in days?

Use the Date Difference tab, enter the birth date as the start date and today as the end date. The total days shown is the person's age in days.

Does this account for leap years?

Yes. The calculation uses actual calendar arithmetic, so February 29 in leap years is handled correctly.

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Date Calculator

Calculate the difference between two dates or add/subtract days, weeks, months, and years from any date.

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About this tool

Two tools in one: calculate the exact duration between two dates (years, months, weeks, days), or add and subtract time from any date to find a future or past date. Handles leap years, DST, and month-length variations correctly.

How to use

1 Select the 'Difference' tab to find how many days/months/years are between two dates.
2 Or use the 'Add/Subtract' tab to find a date that is N days from a starting date.
3 Enter your dates using the date picker.
4 See the result broken down into years, months, weeks, and days.

Frequently Asked Questions

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