Age Calculator
Work out an exact age in years, months and days, on today's date or any other. For the exact age on one specific date, past or future, use the age calculator between two dates.
How the count works
Age is counted in complete units, largest first. The calculator finds how many whole years fit between the two dates, then how many whole months fit in what is left, then counts the remaining days.
This is why someone born on 15 June 1990, checked on 10 June 2026, is 35 years, 11 months and 26 days rather than 36. The final birthday has not arrived yet, so the year does not count.
The 29 February question
Someone born on 29 February has no birthday in three years out of four. The convention used here, and in most legal systems, is that their birthday falls on 28 February in a non-leap year. They turn a year older on that date and reach the age of majority on the same schedule as anyone else.
A few jurisdictions use 1 March instead. The difference only matters for a single day and only for people born on a leap day, but if you are checking a legal threshold it is worth confirming which rule applies. The years/months/days breakdown itself follows the same 28 February anniversary when counting whole years and months, so the remaining-days figure is measured from that same date rather than from a 29 February that does not exist in that year.
Total days and why it is not a round number
The day count includes every leap day in the span. Over a 40-year life that is around 10 extra days compared to multiplying by 365. The exact figure depends on whether a century year falls inside the range, since 1900 and 2100 are not leap years while 2000 was.
Common questions
How Age Calculators Work
An age calculator measures the time between a date of birth and a reference date — usually today. The result is expressed in years, months, and days rather than just total days, because people think about age in calendar terms. A person born on 15 June 1990 is 36 years old today, not 13,252 days old, even though both statements are mathematically true.
The calculation method
- Count complete years first. A birthday marks the completion of a year. If today is before this year's birthday, subtract one from the year count.
- Count remaining complete months. Walk forward month by month from the last birthday until you cannot fit another full month before today.
- Count remaining days. The leftover days are the days since the last full-month boundary.
This is why your age on your birthday is a clean number of years with zero months and zero days — the year boundary and the day boundary coincide exactly.
Leap year birthdays
If you were born on 29 February, your birthday falls on a real calendar date only in leap years. In other years, most legal and official systems treat either 28 February or 1 March as your legal birthday, depending on jurisdiction. Our calculator uses 28 February as the fallback in non-leap years, which is the most common convention for date arithmetic.
Common uses for an age calculator
- Personal milestones: Confirm the exact date you turn 18, 21, 25, 40, 65, or any other milestone age.
- Pension and retirement eligibility: Many pension schemes require a precise age — not just the year — before you can draw benefits. Knowing the exact date you qualify helps you plan withdrawals.
- School year cut-offs: School admissions offices use a specific age on a specific date to determine which school year a child enters. Parents often need to check whether a child is old enough by the registration deadline.
- Medical age requirements: Some vaccines, screenings, and medication doses are age-dependent. A GP or pharmacist may ask for exact age in months for young children, not just years.
- Legal age verification: Buying alcohol, signing contracts, voting, and driving all require age checks. This calculator gives you the precise date on which those ages are reached.
- Insurance waiting periods: Life and health insurers sometimes base premiums on your age at the time of application. Applying before or after a birthday can change your premium band.
- Pet age: Veterinary care is often recommended on age-based schedules. Knowing your pet's exact age in months helps you track vaccination and checkup intervals.
Age in different formats
Our calculator shows your age in years, months, and days — but also gives totals in just months and just days. This is useful when you need a single number. For example, a paediatrician might record a premature infant's age in total weeks. A loan officer might need the number of complete months a customer has been employed. The total-days figure is also used for calculating the number of days between two dates precisely.
What "exact age" means
Exact age means the age at the moment of the calculation. If you run this calculator at 09:00 on your birthday, you are technically zero hours into your new year of age. We work to calendar dates only — the time of day is not considered. For most legal and practical purposes, you reach an age on the calendar date of your birthday, not at the specific hour of your birth.
Quick tip: bookmark this free age calculator to check anyone's exact age in seconds. If you're curious about the calendar rules behind the calculation, see Wikipedia's leap year article. You can run this age calculator for any reference date — not just today — and it always returns an exact age instantly. From milestone birthdays to retirement planning, an age calculator takes the guesswork out of exact ages.
Who uses an age calculator? Parents checking school cut-off dates, HR teams planning retirements, and anyone settling a birthday debate. This free age calculator serves them all — enter any date of birth and get an exact age in years, months, and days. Bookmark this age calculator for the next milestone.