Age Calculator
Exact age from a date of birth, on today’s date or any other.
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Defaults to today. Change it to work out an age on any other date.
Enter a date of birth to calculate an exact age.
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How it works
To calculate an exact age, enter the date of birth above — the result is shown in years, months, and days, along with the total number of months, weeks, and days lived and the date of the next birthday.
Age is counted the way people and legal systems count it: you are a year older on the anniversary of your birth, not after 365 days have elapsed. Those are different, because leap years mean a year is sometimes 366 days. The calculation here works in whole calendar months from the birth date, then measures the remainder in exact days, so the answer matches what you would get by counting birthdays on a calendar. It is the same years-months-days arithmetic as the date difference calculator, anchored to a birth date.
The "age on" field defaults to today but takes any date. That covers the cases this is most often needed for beyond curiosity: working out how old someone will be at an event, checking an age on a specific cut-off date for a school year or a competition category, or reconstructing an age from a historical record. For the time left until a birthday or the event itself, make a shareable countdown.
A 29 February birthday has no anniversary in most years, and there is no single correct rule for what happens then — it is a legal question rather than an arithmetic one. This page treats 28 February as the birthday in non-leap years, the convention used in the UK and in most of the United States, and says so on screen when it applies. Some jurisdictions, including parts of continental Europe and New Zealand, treat 1 March as the legal date instead. If the answer matters for something official, check which rule applies where you are.
The total-days figure is an exact count of calendar days including every leap day, so it is not the years figure multiplied by 365. Hours are that day count multiplied by 24 and, as with any long span, will be an hour or two out from true elapsed time if the period crosses daylight saving changes. To find which weekday a birthday falls on in a given year, look up the day of the week.
FAQ
How do I calculate my exact age?
Enter your date of birth above. The age appears immediately in years, months, and days, calculated from today unless you change the "age on" date.
How old am I in days?
The total days figure is shown alongside the main result. It is an exact count of calendar days including leap days, which is why it is not simply your age in years times 365.
How does this handle a 29 February birthday?
In non-leap years the birthday is treated as 28 February, which is the convention in the UK and most of the US. The tool says so on screen. Some jurisdictions use 1 March instead, so check locally if it matters legally.
Can I calculate age on a future or past date?
Yes. Change the "age on" field to any date and the result is calculated against that instead of today — useful for age cut-offs, school years, and eligibility dates.
Is my date of birth stored or sent anywhere?
No. The calculation happens in your browser and the network monitor on this page shows that nothing is transmitted. Nothing is saved when you close the tab.