Age Calculator
Enter a birthdate (and optionally a reference date) to compute your chronological age in whole years.
Calculator
Use the Age Calculator
Result
—
Formula
completed years since birthdate
Step-by-step
- 1
Enter the birthdate
Use YYYY-MM-DD format.
- 2
Optionally pick a date
Defaults to today if empty.
Worked example
Example input: birthdate: 1990-06-15, onDate: 2026-06-15
Result: 36
Related tools
- Date Difference
Days between two dates.
Frequently asked questions
How is the age computed?
By whole calendar years between the birth date and the reference date. If the birthday has not arrived yet in that year, one year is subtracted — someone born in December 2000 is still 25 in October 2026. The reference date defaults to today, which is why the printed number updates on its own as calendars turn.
What happens on the birthday itself?
The birthday counts as reached: a person born 12 March 2004 turns 22 exactly on 12 March 2026. Both dates are compared as calendar days, so a leap-year birthday also behaves correctly.
Can I compute age at a past or future date?
Yes — enter any reference date alongside the birth date. That answers questions like how old was someone at graduation, or how old they will be on a coming appointment date.
What is chronological age?
Chronological age is the time elapsed since birth, measured in whole completed years. For example, someone born on 15 January 1990 has a chronological age of 36 on 8 November 2026 — enter birthdate 1990-01-15 and reference date 2026-11-08 to reproduce it.
How do you calculate your age by hand?
Subtract the birth year from the current year, then subtract one more if the birthday has not happened yet this year. Example: born 31 December 1987, on 8 November 2026 that is 2026 − 1987 = 39, minus 1 because the birthday has not yet arrived — age 38.
How are February 29 birthdays handled?
Leap-day birthdays use ordinary calendar arithmetic: someone born on 29 February 2000 is 26 on 8 November 2026. Enter birthdate 2000-02-29 with any reference date to confirm the count.
How old will I be in a future year?
Enter the future date in the reference field: a child born on 1 January 2020 is exactly 10 years old on 1 January 2030. Future reference dates go through the same calendar rule, so planned-age questions (documents, sports age groups, senior benefits) resolve directly.
Can I use this age calculator for a child?
Yes — any birthdate works: born 4 July 2010 gives age 16 on 8 November 2026. For infants and toddlers where exact months and days matter more, the Date Difference calculator counts the days between the birth date and today.