How is the exact age calculated?

The calculator subtracts your date of birth from today's date, accounting for varying month lengths and leap years. The result is expressed as complete years, complete months, and remaining days — not just a rounded year count.

How does the months-and-days breakdown handle different month lengths?

When today's day-of-month is earlier than your birth day, the tool borrows the number of days in the previous calendar month, then carries down a month. This is why the same age can show 29, 30 or 31 "borrowed" days depending on which months are involved.

Are leap years counted correctly?

Yes. The total-days figure is the true number of calendar days between the two dates, so every 29 February you have lived through is included automatically.

How is the next-birthday countdown worked out?

The tool builds your birthday in the current year; if that date has already passed (or is today), it rolls forward to next year, then counts the whole days until then. On the day itself it shows "Today!".

How many days are there in a year of age?

A common (non-leap) year has 365 days and a leap year 366, so an average year is about 365.25 days. The calculator does not approximate — it counts the exact days between your birth date and today.

Is my date of birth stored or sent anywhere?

No. The calculation runs entirely in your browser using JavaScript's built-in Date object. Your date of birth is never transmitted to a server, stored in a database, or logged in any way.

Age Calculator — Gera Tools

Age calculator — exact years, months, days and birthday countdown

Enter your date of birth and this calculator instantly shows your exact age broken down into years, months and remaining days — not just a rounded figure. Handy for forms that need an exact age, for milestone birthdays, and for satisfying curiosity about how many days you have been alive.

How it works

The calculator takes the difference between today and your date of birth in three parts. It subtracts the birth year, month and day from today’s, then borrows where needed: if the day count goes negative it adds the number of days in the previous month and drops one from the month count; if the month count then goes negative it adds 12 and drops one from the years. Totals are computed separately from the raw millisecond gap — total days, then weeks (days ÷ 7) and hours (days × 24). The next birthday is your birth month and day in the current year, rolled to next year if it has already passed.

Example

For a date of birth of 1 January 1990, on 30 May 2026 the calculator shows an age of 36 years, 4 months, 29 days, roughly 13,298 total days and about 1,899 weeks, with the next birthday on 1 January 2027.

Output	What it means
Age	Complete years, months and remaining days
Total days	Exact calendar days lived (leap days included)
Total weeks	Total days ÷ 7, rounded down
Total hours	Total days × 24
Next birthday	Date and number of days until it

Everything runs entirely in your browser — your date of birth is never uploaded or stored.