Age Calculator

Subtract your birth date from today's date. The result is your age in years, months, and days. For example, if you were born on March 15, 1995 and today is May 24, 2026: 2026 − 1995 = 31 years, then count from March 15 to May 24 = 2 months and 9 days. So you're 31 years, 2 months, and 9 days old.

Subtract your birth year from the current year (2026). If your birthday has already passed this year, that's your age. If it hasn't passed yet, subtract 1 from that number. Example: born in 1995, today is May 24, 2026. If your birthday is before May 24, you're 31. If after, you're 30.

For someone over a year old, multiply their age in years by 12 and add the remaining months. For infants, count from the birth date to today in completed months. Example: born March 1, 2025, today is May 24, 2026 = 14 months old (1 year, 2 months, and a few days).

Divide the total days since birth by 7. The calculator above shows total weeks directly. For newborns and infants, parents and pediatricians often track age in weeks because development happens quickly. Example: born May 1, 2026, today is May 24, 2026 = 23 days = about 3 weeks old.

In leap years (every 4 years), they celebrate their actual birthday on February 29. In non-leap years, most people default to March 1 (sometimes February 28). Legally and for age calculation purposes, they age one year on the same day everyone else would — they just have to pick a date in non-leap years.

Use the calculator above and change the 'Calculate age on' field to the date you want. The calculator will tell you exactly how old you were on that date. This is useful for filling out historical forms, calculating age at a past event, or doing genealogy research.

The calculator above shows your total days alive. As a quick estimate: multiply your age in years by 365 and add 1 day for every 4 years (for leap years). Example: 30 years old ≈ 30 × 365 + 7 = 10,957 days. Add or subtract days based on how far you are from your last birthday.

Chronological age is the time since you were born — what this calculator shows. Biological age is an estimate of how old your body 'seems' based on health markers like blood pressure, cholesterol, fitness, and cellular aging. Biological age can be higher or lower than chronological age. This calculator handles chronological age only.

This calculator uses the Western system: age starts at 0 at birth and increases by 1 on each birthday. Some cultures (notably traditional Chinese) count age starting at 1 at birth, with age increasing at the lunar new year rather than the birthday. For Western forms, use the result this calculator shows. For traditional Chinese age, add 1-2 years depending on the date and convention.

'Total months' adds up all months as if they were equal — a useful average. 'Years + months + days' uses exact calendar arithmetic, which is what most people mean by 'age.' For example, 1 year, 6 months, 0 days = 18 total months exactly. But 1 year, 6 months, 15 days might be 18 'months' in everyday speech even though it's slightly more.