How to use the age calculator
Enter a date of birth to see the exact age today in years, months and days. You'll also see the total
number of months, weeks and days, which day of the week the person was born on, and how long until the
next birthday. Change the second date to work out an age on any other day.
How age is calculated
- Subtract the birth year from the current year.
- If this year's birthday hasn't happened yet, subtract one year.
- Count the whole months since the last birthday, then the remaining days.
For example, someone born on June 15, 1990 is 35 years, 3 months and 20 days old on October 5, 2025.
Common uses
- Checking age requirements for school, sports, licenses or retirement
- Filling in forms that ask for age in years and months
- Working out a child's age in months
- Counting the days until a birthday or anniversary
Frequently asked questions
How is age calculated?
Age is counted in completed years, months and days. If today's day of the month is earlier than your birth day, a month hasn't been completed yet, so the calculator borrows the days from the previous month.
How are leap-year birthdays (February 29) handled?
In years without a February 29, this calculator treats February 28 as the birthday. Some people celebrate on March 1 instead; legally, the rule differs between countries.
Can I calculate age on a specific date?
Yes. Change the “Age on” date to any date in the past or future, for example to check how old someone will be on a deadline or how old they were at a past event.
Why do some countries count age differently?
The traditional East Asian system counts a person as 1 at birth and adds a year every New Year. South Korea officially switched to the international system in 2023. This calculator uses the international method.