Age calculator
Your exact age in years, months and days, from any date of birth.
Dates
Any date from the year 1 onwards.
Today unless you change it.
Enter a date of birth to see the age.
Related tools
Type a date of birth and read the age in years, months and days, counted on the real calendar. Use it when a form asks for an exact age, when you need to know how old someone will be on a given day, or when you want the plain number of days you have been alive. The second field starts on today and moves to any date you like. The arithmetic runs in the page: your date of birth is never uploaded.
How to use
- Pick the date of birth in the first field.
- Leave the second field on today, or set another date.
- Read the age in years, months and days under the fields.
- Check the tiles for total days, weeks, hours and the next birthday.
- Press Copy to take the result as text.
What it handles
- Month lengths are counted, never averaged: 31 January to 1 March is one month and one day.
- Leap years follow the Gregorian rule, so 1900 has no 29 February and 2000 has one.
- A 29 February date of birth has its birthday on 28 February in a common year.
- Dates back to the year 1 work, on the proleptic Gregorian calendar.
- Both fields are calendar dates in your own time zone, so nothing slips by a day.
- A date of birth in the future is reported as such, not as a negative age.
FAQ
How is a 29 February birthday counted in a common year?
This tool uses 28 February, the last day of that February. Someone born on 29 February 2000 turns 25 on 28 February 2025. Other calculators pick 1 March; the two differ for one day a year. The years, the months and the countdown here all follow the same rule.
Does my date of birth leave my browser?
No. There is no server side to this tool: the page does the arithmetic itself and works with the connection off. Both dates go into the address bar so a link reproduces the result, which means they travel only if you send that link. The date of birth is also kept in this browser, and Clear removes it.
Why not just divide the days by 365?
Because that is wrong by a day or more for most people. A year is 365 or 366 days, a month is 28 to 31, and the mix differs for every birth date. This tool counts calendar months and calendar days, so the years tick over on the birthday itself.
Can I use a date before 1900?
Yes. Any year from 1 to 9999 is accepted in both fields, and old dates use the same day counting as recent ones. The calendar is the proleptic Gregorian one, so a date recorded in the Julian calendar will differ by several days from a historical source.
What happens if the date of birth is in the future?
The tool says so in one line and shows how many days away that date is, rather than printing a negative age. The same happens when the second date is earlier than the date of birth. Setting the second field ahead is fine: it gives the age someone will have reached by then.
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