Age calculator — exact age in years, months and days
Work out your exact age in years, months and days, plus total weeks, hours and minutes lived, the day you were born and your next birthday.
- Runs in your browser
- Nothing you enter is sent
- Free, no account
Defaults to today. Past or future both work.
Sets what counts as “today” and how the hours lived are measured.
Enter a date of birth to see the exact age, every total, and the next birthday countdown.
How to use the age calculator
- Enter the date of birth. Any date from year 1 to year 9999 works, including dates before 1970.
- Leave Age at date on today for the current age, or change it to work out how old someone was — or will be — on a specific day.
- Turn on I know my time of birth if you want the hour-level totals to be exact. It also makes the final day of the breakdown roll over at the real minute of birth rather than at midnight.
- Check the reference timezone. It decides what counts as "today", which can change the answer by one day if you are near midnight or looking up an age in another country.
How exact age is calculated
Age is not a division. Dividing elapsed days by 365.25 gives a decimal that no form, school or immigration office accepts. The convention used here — and by every legal system that defines the term — is a calendar walk in three steps:
- Count whole years from the date of birth to the reference date.
- From that anniversary, count whole calendar months.
- Whatever days are left over are the day component.
Because step two respects real month lengths, 31 January to 1 March is "1 month, 1 day" in a leap year and "1 month, 1 day" in a common year too — the month component absorbs the difference. The totals shown underneath are a separate measurement: they count real elapsed time, so every leap day you have lived through is included.
People born on 29 February
A leap-day birthday has no anniversary in three years out of four. This calculator follows the most common civil convention and treats 28 February as the anniversary in common years, which is also what most databases and calendar libraries do. Some jurisdictions use 1 March instead, so if a legal deadline depends on it, check the local rule. Your total days lived is unaffected either way.
Why the timezone matters
"How old am I" depends on today's date, and today's date depends on where you are. When it is 23:30 on Tuesday in Los Angeles it is already Wednesday in London, so the two answers can differ by a day. If you were born abroad and want the age your birth certificate implies, set the reference timezone to the country of birth.
What each total actually measures
| Figure | Meaning | Typical use |
|---|---|---|
| Years, months, days | Whole calendar units, counted in that order | Forms, medical records, school entry, visas |
| Total days | Whole calendar days between the two dates | Milestone birthdays such as the 10,000th day |
| Total months | Whole calendar months, so 12 per year exactly | Infant development charts, subscription age |
| Total hours and minutes | Real elapsed time, including leap days and DST shifts | Curiosity, birthday-party trivia, precise anniversaries |
Milestone birthdays worth knowing
- 1,000 days — about 2 years and 9 months.
- 10,000 days — about 27 years and 4 months.
- 1 billion seconds — 31 years, 251 days and change.
- 20,000 days — about 54 years and 9 months.
Set the Age at date field forwards and watch the total-days figure to find the exact day any of these lands on.
Privacy
A date of birth is one of the most useful pieces of information an identity thief can hold, which is why this page has no analytics, no forms and no network requests at all. The calculation runs in your browser, the value is never stored, and closing the tab erases it.
Questions
How is exact age in years, months and days calculated?
Whole years are counted first, then whole months from that anniversary, then the leftover days. It is the same convention hospitals, visa forms and school registrars use, so 1 March minus 1 January is "2 months, 0 days", never 59 days rounded.
What happens if I was born on 29 February?
In non-leap years the anniversary is treated as 28 February, which is how most legal systems and calendar libraries handle it. Your total-days figure is unaffected — it counts real elapsed days either way.
Does the timezone matter?
It changes what "today" means, which can shift your age by one day around midnight. The calculator states which timezone it is using and lets you change it, so you can compute an age as of the country you were born in.
Can I calculate my age on a future or past date?
Yes. Set the "age at date" field to any date and the whole breakdown — years, months, days, totals and weekday — is recomputed as of that date instead of today.
Is my date of birth sent anywhere?
No. The page contains no network calls at all; the arithmetic runs in your browser tab and nothing is stored or transmitted.