Calculators

Age Calculator

Enter a date of birth and get an exact age in years, months and days, the total days and weeks lived, and how long there is until the next birthday.

How old am I?

Enter the day you were born. Nothing you type is saved or sent anywhere until you press Save this age.

Your exact age appears here — years, months and days.

Saved ages

Kept on this device, and on your account when you're signed in. Add a note to remember whose birthday each one is.

Type a date of birth and the panel above answers the question people actually mean by "how old am I" — years, months and days, worked out from calendar dates rather than rounded off a rough estimate. Underneath that headline figure you also get the day of the week you were born on, the total days and weeks you've been alive, and how long is left until the next birthday. Nothing you type is sent anywhere; the whole calculation runs in your browser, and the date of birth only leaves this page if you deliberately choose to save it.

Age on a specific date

The second field, "Age on this date", is filled with today's date to start with, but it doesn't have to stay there. Change it and every figure on the page — years, months, days, days lived, weeks lived and the next-birthday tile — recalculates for that date instead of today.

That turns the tool into an answer for two different kinds of question. Set it to a date in the past to find out how old someone was when something happened: when a photo was taken, when a contract was signed, or how old a historical figure was on a specific event date. Set it to a date in the future to work out an age ahead of time — how old you'll be on a wedding day, a graduation, or the date a rule with an age cutoff takes effect. The field only rejects one thing: a date of birth that falls after the date you're checking, since there's no sensible age to report for that pairing, and the tool tells you which of the two fields to change rather than guessing. A "Use today" button appears next to the field once you've moved it away from today, so getting back doesn't mean retyping the date by hand.

Why this tool's answer might not match another calculator

Every calendar-based age calculator has to decide what happens when an anniversary lands on a day a month doesn't have, and calculators disagree about it more often than the arithmetic looks like it should allow. This one uses a single rule for both the monthly figure and the yearly one: an anniversary that would fall on a day-of-month a target month doesn't have is clamped to the last day of that month instead.

The clearest case is 31 January. Its one-month anniversary is the last day of February, so 1 March comes out as "1 month 1 day" — not "1 month 2 days", and never a negative day count, which is what a calculator that borrows from the previous month can produce for the same pair of dates. The same rule governs a birthday on 29 February: in a year without a 29 February, the birthday lands on 28 February. When you enter a date of birth of 29 February, the result panel says so directly, underneath the years-months-days figure, because it's the one case where knowing the convention actually changes what date you'd otherwise assume your birthday is on. Some countries' laws instead treat 1 March as the legal birthday in a non-leap year — this tool states its own convention rather than picking a side on which one is "correct".

Days lived, weeks lived, and your next birthday

The three smaller figures below the main result answer questions the headline age doesn't. "Days lived" is the whole number of calendar days between your date of birth and the date you're checking — a plain count, not an estimate, and worked out from calendar dates so a daylight-saving change partway through your life doesn't shift it by an hour either way. "Weeks lived" is the same span in whole weeks, with whatever days are left over stated alongside it.

"Next birthday" counts forward from whichever date is in the "Age on this date" field, not necessarily from today, so if you've set that field to a date in the past or future you'll see the next birthday relative to that date rather than to right now. It shows how many days away it is, the date and day of the week it falls on, and the age you'll turn. On the day itself it simply says "Today" and names the age you're turning, rather than counting down to zero.

Saving an age you've worked out

Nothing is kept unless you press "Save this age". That's true while you're typing, true the moment a result first appears, and true if you close the tab without touching the button — there's no autosave and no "remember my date of birth" between visits, so a returning visitor always starts from an empty date-of-birth field. Pressing the button keeps the date of birth, the date it was worked out for, and the years/months/days/days-lived figures on this device, and additionally on your account if you're signed in, in the "Saved ages" list below the calculator. Each saved entry can be given a note — useful for remembering whose birthday a particular entry is once you've saved a few — and removed individually from that list; clearing the calculator above it never touches anything you've already saved.

Questions

How do I find out how old I was on a specific date, not today?
Change the second field, 'Age on this date', to whatever date you want the answer for instead of today — it defaults to today but accepts any date on or after the date of birth, past or future. That covers both directions: how old someone was on a date that already happened (when a document was signed, when a photo was taken, when a rule or eligibility test applied) and how old you or someone else will be on a date that hasn't happened yet, such as a graduation, a policy renewal or a birthday a few years out. The years, months, days, days-lived and next-birthday figures all recalculate for whichever date is in that field, and a 'Use today' shortcut appears once you've moved it away from today so you can get back without retyping it.
If I was born on 29 February, is my birthday 28 February or 1 March?
Because three years out of every four don't have a 29 February to land on. This tool uses one rule for every anniversary that falls on a day-of-month a target month doesn't have: it clamps to the last day of that month. For a 29 February birth, that means 28 February in a year without a leap day and 29 February in one that has it. It's a genuine convention rather than the only possible answer — some countries' laws instead treat 1 March as the legal birthday in a non-leap year — which is exactly why this tool states the rule in words under the result whenever the date of birth you entered is 29 February, rather than leaving you to work out which convention you landed on.
Why do different age calculators give different answers for the same two dates?
Almost always because they handle a short month differently, and 31 January is the date that exposes it. This tool's one-month anniversary of 31 January is the last day of February — 28th most years, 29th in a leap year — so 1 March comes out as '1 month 1 day', never a negative day count and never '1 month 2 days'. A calculator that instead subtracts day-of-month fields and borrows when the result goes negative lands on a different day count for that same pair of dates. Both are internally consistent conventions; they just don't agree with each other, which is the actual reason two sites can give two different answers to what looks like the same simple subtraction.
Is my date of birth sent to a server or saved automatically?
No. Every date you type and every figure on screen is worked out inside your own browser, and nothing you type is sent anywhere as you type, when a result appears, or when you close the tab. The only way a date of birth is stored at all is pressing 'Save this age', which is a deliberate action and never happens on its own — not on typing, not when the answer appears, not on a timer. A saved entry is then kept on this device, and additionally on your account if you're signed in, so you can find it again later in the saved-ages list below the calculator.
How many days have I been alive?
The 'Days lived' figure under your result is the whole number of calendar days between your date of birth and whichever date is in the 'Age on this date' field, counted as calendar dates rather than a millisecond or hour difference — which matters because a plain time-based subtraction can be thrown off by a daylight-saving change landing between the two dates. 'Weeks lived' is the same count divided into whole weeks plus the odd days left over, so you can read your time alive in whichever unit is more useful to you.