Age Calculator
An age calculator that counts calendar months properly rather than dividing by 365.25 — giving your exact age in years, months and days, everything you have lived through in other units, and a countdown to your next birthday.
How to use Age Calculator
- Enter your date of birth. The result appears immediately.
- Read your exact age in years, months and days, plus totals in months, weeks, days, hours and minutes.
- Check the weekday you were born on and the countdown to your next birthday.
- Switch to “age on a date” to work out how old you were, or will be, on any other date.
About Age Calculator
Age looks like a trivial calculation and is not. Divide the days between two dates by 365.25 and you get a number that is close but wrong — sometimes by a day either side of a birthday, which is precisely when the answer matters. Real age is calendar arithmetic: count the whole years, then the whole months, then the leftover days, borrowing from the correct preceding month when the day-of-month goes negative. That is how this calculator works, and it is why the result flips to a new year on exactly the right morning.
Around the exact age it adds the figures people actually search for: total months, weeks, days, hours and minutes lived, the day of the week you were born on, how many days remain until your next birthday and which weekday that will land on. The totals are computed from real elapsed calendar time, so leap days and the varying lengths of months are all accounted for rather than smoothed over with an average.
The 29 February case is handled explicitly instead of being quietly fudged. A leapling has no birthday in three years out of four, and different legal systems resolve this differently — English and most US practice treats the anniversary as 28 February, while some jurisdictions use 1 March. The tool applies the 28 February convention, says so on screen, and still counts the exact number of days so you can reason about it yourself. The “age on a date” mode uses the same logic for any target date, past or future.
Frequently asked questions
How is exact age calculated?
By calendar arithmetic, not division. The tool counts whole years from your birth date, then whole months, then the remaining days — borrowing the correct number of days from the preceding month when needed. Dividing total days by 365.25 gives a slightly different answer and is not how anyone actually counts age.
How is age handled for a 29 February birthday?
In common years the tool treats 28 February as the birthday, which matches the convention used in England, Wales and most of the United States. Some jurisdictions (and New Zealand) use 1 March instead. The difference is one day, and the tool states which convention it applied.
Why does my age in months not match total days ÷ 30?
Because months are not 30 days. The total-months figure counts actual calendar months elapsed, so it changes on your monthly “month-day” anniversary rather than every 30 days. Both figures are shown so you can see the difference.
Does it account for time zones?
Dates are treated in your local calendar, which is what you want for a birthday: being born on 3 May means you turn a year older on 3 May wherever you are, regardless of the UTC offset at the moment of birth.
Can I calculate someone’s age on a past or future date?
Yes. The “age on a date” mode takes any target date and reports the age on that day, which is how you check eligibility cut-offs, school year groups or historical ages.
Is my date of birth stored anywhere?
No. It never leaves your browser and is not sent to any server. Nothing is logged.
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