Age Calculator

An age calculator tells you exactly how old you are in years, months, and days — and how many total days you've lived — from your date of birth. It handles leap years and varying month lengths correctly, so the count is accurate to the day. Leave the second date blank to calculate age as of today, or set it to work out age on any past or future date, which is what eligibility rules, admissions and pension cut-offs actually ask for. Dates are read as whole calendar dates, so the time you were born and the time zone you are in now make no difference to the answer. It all runs in your browser.

How to use it

1. Enter your date of birth.
2. Leave the second date blank for today, or pick any date to calculate age as of then.
3. See your age in years, months, and days, plus the total days lived.
4. For an eligibility check, set the second date to the cut-off printed in the rules rather than to today — that is the age the form is asking for.

Examples

• Born 1990-05-15, as on 2026-07-17 → 36 years, 2 months, 2 days.
• That's 13,212 total days.
• Born 2004-02-29, as on 2026-02-28 → 21 years, 11 months, 30 days; one day later it becomes 22 years exactly.
• Born 2000-07-18, as on 2026-07-17 → 25 years, 11 months, 29 days — a year is not complete until the day itself.

Frequently asked questions

How is age calculated exactly?

Age is the completed years, months, and days between your birth date and the chosen date. The calculator subtracts date parts and borrows from months when needed — using the real length of each month — so the result is accurate to the day.

How do leap years affect my age?

For most people, not at all: you complete another year on your birth date whatever the calendar does, and the extra 29 Februaries show up only in the total-days figure. Leap-day births are the exception. For someone born on 29 February 2004, this calculator reads 21 years, 11 months and 30 days on 28 February 2026, and a full 22 years on 1 March — because that year has no 29 February to complete the year on. Countries differ on which of those two dates counts as the legal birthday, so check the rule rather than the calculator for anything official.

What is my age for school/exam eligibility?

Most eligibility rules require an exact age as of a specific cut-off date. Set the second date to that cut-off and read the years and months — that's the figure boards and admissions use.

How many days old am I?

The calculator shows total days lived alongside your age. It is the exact count of calendar days from your birth date to the chosen date, leap days included — which is why it is not your age in years multiplied by 365. That shortcut loses a day for every leap year you have lived through, nine of them by the age of 36. The worked example on this page, born 15 May 1990 and read on 17 July 2026, comes to 13,212 days: 36 completed years, nine leap days, and the 63 days since the last birthday.

Why does an official form give a different age from this?

Almost always because it is asking as at a different date. Exam boards, admissions and recruitment set a cut-off — one fixed date the whole cohort is measured against — so the age the form wants is your age on that date, not today. Set the second field to the cut-off and the two will agree. The other common cause is a form that wants completed years only, which means dropping the months and days entirely rather than rounding them up.

Why is a baby's age given in months?

Because years are too coarse to be useful in the first few of them, and growth charts and developmental milestones are all indexed on months. This calculator gives the months directly: a child born on 3 April 2025 is 1 year and 4 months on 6 August 2026, which those charts read as 16 months. Where a form wants a single figure in months, multiply the years by twelve and add the months shown.

Can I work out my age on a future date?

Yes — the second field takes any date, past or future, so you can check the age you will be on an exam day, a policy maturity date or a retirement cut-off. The only rule the tool enforces is that the birth date has to come first; a birth date later than the as-on date is rejected rather than silently reported as a negative age.