Age Calculator
Calculate your exact age from a birth date.
Calculating…
Calculated as of today, ….
Use on any page (bookmarklet)
Want Age Calculator without leaving the page you're on? Drag the button below to your bookmarks bar, then click it on any website to open Age Calculator right there — it runs entirely in your browser.
Use responsibly: a bookmarklet runs on whatever page you click it on. Avoid sensitive sites such as online banking, payment, or healthcare pages — you run it at your own risk. Everything is processed locally and no data is sent anywhere. See our Terms.
- Show your bookmarks bar if it's hidden — Ctrl+Shift+B (⌘+Shift+B on Mac).
- Drag the button above onto the bookmarks bar.
- Open any website and click the bookmark — the Age Calculator panel appears in the top-right corner. Use ✛ to move it between corners, or ›/‹ to tuck it against the edge and pull it back out.
- Click the bookmark again (or the ✕) to close it.
Note: a few sites with strict security policies may block bookmarklets.
Examples
Age from a birth date
Input
Born 2000-01-01
Output
e.g. 25 years, 5 months, 23 days · ~9,300 days
Next birthday
Input
Born 1990-12-25
Output
Shows days remaining until December 25
About this tool
This free online age calculator works out your exact age from your date of birth. It shows your age in years, months, and days as of today, your total days and weeks lived, the day of the week you were born, and how long until your next birthday. Everything runs in your browser with no upload.
How to use
- Enter your date of birth.
- Read your age breakdown and totals.
- Check the countdown to your next birthday.
Why age isn't days ÷ 365
A calendar year averages 365.2425 days, so dividing your total days by 365 quietly overstates your age — by about a day for every four years lived. Age is a calendar count, not a duration: it increments when the date rolls past your birthday, regardless of how many days that took. That is why the total days figure here is not your age multiplied by 365, and why the gap widens the older you get.
Born on 29 February
Leap-day birthdays have no universally correct answer. In common years there is no 29 February to reach, so jurisdictions differ: many treat 1 March as the legal birthday, on the grounds that it is the day after February ends; others use 28 February so the birthday stays within the same month. Both are defensible and both are used in practice. The age in complete years works out the same either way — the disagreement is only about which day you celebrate, and it matters legally in the narrow window between the two dates.
Age reckoning is not universal
The years-months-days figure shown here is the international convention — you are zero on the day you are born and gain a year on each birthday. It is not the only system. Traditional East Asian age reckoning counts a newborn as one and adds a year at the new year rather than the birthday, which can put someone up to two years older than their international age. South Korea moved to the international system for most official purposes in 2023, but the traditional count still appears in everyday conversation, so it is worth asking which is meant when the number matters.
Common uses
Filling in an exact age on a form or application, checking eligibility thresholds for a licence, pension, or scheme, working out how many days you have been alive, and counting down to the next birthday. Your date of birth is processed entirely in your browser and never uploaded. To measure a gap between two arbitrary dates instead, use date difference, and for pets there is a dedicated pet age calculator with species-specific life stages.
Frequently asked questions
How do I calculate my exact age?
Enter your date of birth and the calculator shows your age in years, months, and days as of today, plus your total days lived and the weekday you were born on.
When does someone born on 29 February have a birthday?
Legally it depends where you are, which is why there is no single right answer. Most jurisdictions treat 1 March as the birthday in common years, since that is the day after the last day of February; some treat 28 February instead. This calculator counts complete years elapsed, so a leaper's age increments once the date has passed either way — the ambiguity only affects which of the two days you celebrate.
Does it count leap years correctly?
Yes. It walks real calendar months and years rather than assuming 365 days, so 29 February and varying month lengths are handled accurately. This is why the total days lived is not simply your age multiplied by 365 — over 40 years the leap days alone add up to about ten.
Why is my age in years not just days divided by 365?
Because a year is 365.2425 days on average, and your age counts complete calendar years rather than a fixed quantity of days. Dividing days by 365 overstates your age slightly and drifts further as you get older — roughly a full day per four years. Age is a calendar count, not a duration.
Can it tell me when my next birthday is?
Yes. It shows how many days remain until your next birthday, and wishes you a happy birthday if it's today.
What day of the week was I born?
The calculator shows the weekday for your date of birth alongside your age.
Is my birth date uploaded anywhere?
No. Everything is calculated in your browser with no upload, so your date of birth stays private.
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