Age Calculator
The Age Calculator computes a person's age in years and total months from a birth date and the current date. It's the simplest, most accurate way to find someone's age without doing month-arithmetic in your head.
This calculator is useful for:
- Filling out forms that ask for age in years
- Tracking developmental milestones (babies & toddlers)
- Eligibility checks (insurance, school, work)
- Birthday planning (counting how long until the next birthday)
Formula
age in months = (currentYear − birthYear) × 12 + (currentMonth − birthMonth)
age in years = floor(age in months ÷ 12)
By computing months first, the calculator correctly handles people whose birthday hasn't yet occurred this year — they get one fewer full year than the bare year-subtraction would suggest.
How to use
- Enter your birth year and birth month (1 = January, 12 = December).
- Enter the current year and current month.
- The calculator instantly shows your age in years and in total months.
FAQ
Why are days not included?
A full age calculation that tracks days requires real Date arithmetic and time-zone handling. For the vast majority of use cases (forms, eligibility, planning) years + months is sufficient. If you need days, our hours-calculator or month-calculator with manual day entry covers it.
Does this account for leap years?
Years and months are integer subtraction, so leap years don't affect the result. A leap year only adds an extra day in February — it doesn't change the year-and-month count.
What if my birthday is this month but later in the month?
This calculator works at month granularity. If today is the 5th and your birthday is the 28th of the same month, the calculator counts the month as complete. For day-exact age, use a separate days-between calculator.