Calculating your exact age sounds trivial until you factor in leap years, varying month lengths, and whether your birthday has happened yet this year — small details that throw off manual math.
The manual approach
Subtract your birth year from the current year. If your birthday hasn't occurred yet this calendar year, subtract one more. For months and days, count forward from your last birthday to today.
- Years: current year minus birth year (adjust if birthday hasn't passed yet).
- Months: count from your last birthday to the current month.
- Days: count remaining days since your last monthly mark.
Born on February 29th? Most systems treat March 1st as your birthday in non-leap years — worth knowing for legal or contractual age requirements.
For anything official — visas, eligibility checks, contracts — skip the manual math and use our age calculator, which accounts for leap years automatically.
PrimeCalculator Editorial Team
Calculator & Finance Writers