Age Calculator Online Free — Exact Age in Years, Months & Days
Free online age calculator: exact age in years, months and days from a birth date, plus total days, weeks and hours lived and a next-birthday countdown. Computed entirely in your browser.
About Age Calculator
Enter a birth date and get your exact age — years, months, and days — along with the total number of days, weeks, months, and hours you have been alive. It also counts down to your next birthday and tells you which day of the week it falls on. All the math happens locally in your browser; the date you enter is never sent anywhere.
How to use Age Calculator
- Enter the date of birth.
- Optionally set an "as of" date (defaults to today).
- Click Calculate to see the exact age, totals lived, and the next-birthday countdown.
How age is calculated
The calendar method
Exact age is worked out the way a calendar does it: subtract birth year from today's year, then back off one year if the birthday has not happened yet, and do the same for months within the year. The leftover days come from counting forward from the birth day-of-month to the current date.
Month-length edge cases are handled explicitly — for example, someone born on January 31 completes a new month on March 3 in a non-leap year (February has no 31st), and leap-year birthdays (Feb 29) roll to Mar 1 in common years.
The totals
Total days, weeks, and hours are computed from the raw elapsed time between the two dates (midnight to midnight in your local time zone), so they always add up exactly — 1 day = 24 hours, 7 days = 1 week. Total months is the calendar month difference, which is why it can differ slightly from "total days ÷ 30.44".
The next birthday is the next time the birth month and day occur (Feb 29 birthdays are counted on Mar 1 in common years), and the countdown shows how many days away it is and the weekday it lands on.
Why calculate age in the browser?
A date of birth is personal data, and many age tools quietly POST it to a server. Here the calculation is plain JavaScript Date math running on your device — you can disconnect from the internet after the page loads and it still works.
Frequently asked questions
Is this age calculator really free?
Yes — free, no account, no limits, no ads.
Is my birth date uploaded anywhere?
No. The calculation runs entirely in your browser with JavaScript Date math; nothing is sent to a server and nothing is stored.
What does "as of" mean?
It is the date the age is measured at. It defaults to today, but you can set any date — for example to find out how old someone was on a past date or will be on a future one.
How are leap-year birthdays handled?
If you were born on February 29, your birthday is counted on March 1 in common years and on February 29 in leap years. Month boundaries are handled the same way: a Jan 31 birthday completes a month on Mar 3 when February is too short.
Does it account for time zones or daylight saving?
Both dates are treated as midnight in your local time zone. Totals use the exact elapsed time, so a DST switch day may count 23 or 25 hours — that is the honest answer for your clock.
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