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Date Difference Calculator

Calculate the exact difference between two dates in days, weeks, months, years, hours, and minutes.

Runs 100% in your browser — nothing is uploaded

About this tool

The Date Difference Calculator computes the interval between any two calendar dates and shows the result in six units simultaneously: days, weeks, approximate months, approximate years, hours, and minutes. Enter start and end dates and the numbers update instantly.

Date arithmetic is a common need: counting days until a deadline, calculating age or tenure in years, determining how long ago an event occurred, or figuring out billing periods. Doing this manually with calendars is tedious and error-prone, especially across month boundaries and leap years.

The calculator uses the absolute difference, so you do not need to ensure the start date comes before the end date. Month and year values are approximate (rounded from the total day count) since months have different lengths. All calculation uses the browser's Date API — no server, no library, no network request.

Frequently asked questions

Are months and years exact?
No — they are approximations. Months are calculated as days ÷ 30.44 (average days per month), and years as days ÷ 365.25 (accounting for leap years). For exact calendar month differences, you would need to count actual month boundaries, which is not always meaningful for arbitrary date pairs.
What if I enter the end date before the start date?
The tool computes the absolute difference, so the order does not matter. Days, hours, and minutes are always positive.
Does the calculator account for time zones?
Date inputs (YYYY-MM-DD) are interpreted as local dates at midnight. The difference is computed on the date values only, without time-of-day component. Time zones affect the exact moment of midnight but not the number of calendar days between two dates.
Can I calculate age from a birth date?
Yes — enter the birth date as the start and today's date (pre-filled) as the end. The years field shows the approximate age.

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