Age Calculator
Calculate an exact age in years, months, and days between a date of birth and any date.
How to use this calculator
- Enter a date of birth.
- Optionally enter the date to measure the age at — leave it empty for today.
- Results show calendar age plus totals in days and weeks.
How it works
Age is counted the way people count birthdays: years advance on each birthday, months on each monthly anniversary, and days make up the remainder.
Leap years are handled by the calendar itself — someone born on February 29 gets their next-birthday count measured to February 28 in non-leap years (March 1 in some jurisdictions).
All arithmetic uses UTC dates, so the answer never shifts because of your time zone.
Worked example
Born June 15, 1990; age on August 23, 2026.
- 1Years: 2026 − 1990 = 36 (birthday already passed this year)
- 2Months: August − June = 2
- 3Days: 23 − 15 = 8
36 years, 2 months, 8 days old.
When this calculator is useful
- Filling in official forms
- Eligibility checks with age cutoffs
- Milestone planning (10,000 days old, etc.)
- Genealogy and family records
Frequently asked questions
How is age different from total days?
Calendar age (years/months/days) follows anniversaries; total days is a straight count of 24-hour periods. They answer different questions.
What if I was born on February 29?
The calculator still counts correctly. In non-leap years the next-birthday estimate points to February 28, which is the most common convention.