Age & Date Difference Calculator
Calculate exact age, total days, and total weeks between a start date and a reference date.
How to use
- Enter the base date (e.g. a birth date) in "Start date"
- Enter the date you want to compare against in "Reference date" (defaults to today; reset anytime with the "Today" button)
- Exact duration (years/months/days), total days, total weeks, and the start date's weekday are shown automatically
Useful both for calculating someone's exact age from a birth date and for finding the interval between any two dates.
Example
With start date 2000-04-01 and reference date 2026-07-23, the exact duration is 26 years, 3 months, 22 days, and the total is 9,609 days.
FAQ
Are leap years accounted for?
Yes, the calculation uses JavaScript's Date object, so leap years are handled accurately.
What happens if the reference date is before the start date?
An error message is shown. The reference date must be on or after the start date.
Does it support the East Asian "counting age" (数え年)?
No, only the standard exact age (incremented on each birthday) is supported.
Is my data stored anywhere?
No. Everything runs in your browser and disappears when you reload the page.
Category:Calculators
Tags:agedatedifferencecalculator
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