How to calculate age
To calculate age, subtract the date of birth from today's date: count the full years first, then the leftover full months, then the remaining days.
Example: someone born on 15 March 1990 is, on 20 June 2026, 36 years, 3 months and 5 days old.
Age in days, weeks and hours
Total days is the number of calendar days between the two dates. Divide by 7 for weeks and multiply by 24 for hours. Leap years are handled automatically because the calculator uses real calendar dates.
Use the second date field to find someone's age on any past or future date, such as the day of an event or an exam cut-off.
Chronological age
Chronological age is the time that has passed since birth, given in years, months and days. It is the age used on forms, in school admissions, sports age groups and developmental testing, and it is what this age calculator by date of birth shows.
Age on a specific date
Use the second date to find an age on a past or future day, such as the cut-off date for a school year or a sports league.
📖 Guide: How to Calculate Age From a Date of Birth (Step by Step)
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Frequently asked questions
How is exact age calculated?
Full years are counted first, then the remaining full months, then the remaining days, using the real number of days in each calendar month.
How many days old am I?
Enter your date of birth above and the calculator shows your total days, weeks and hours. As a rough guide, multiply your age in years by 365.25.
Does the calculator handle leap years?
Yes. It uses actual calendar dates. For a 29 February birthday, the next birthday in a non-leap year is counted as 1 March.
Is my date of birth stored anywhere?
No. The calculation runs in your browser and nothing you enter is sent to a server.
What is chronological age?
It is a person's age counted from their date of birth to a chosen date, written in years, months and days.
Can I find an age on a future date?
Yes. Change the second date to any date, past or future, and the calculator shows the age on that day.
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