Age Calculator
Calculate exact age in years, months, days, hours, and minutes from any birthdate. Also shows total days lived and next birthday countdown.
What this calculates
An age calculator gives you the exact difference between two dates: how many years, months, and days have passed. This tool defaults to the time between your birthdate and today, but you can change either date to figure out age at any reference point. It also tells you the total number of days lived and how many days until your next birthday.
Formula & how it works
Age in years is calculated by taking the difference in calendar years, then subtracting one if today's month/day hasn't reached the birth month/day yet. The remaining months and days are filled in from there. Total days is the absolute difference between the two timestamps. Leap years (every 4 years, minus century years not divisible by 400) are handled automatically.
Worked example
Born 1990-06-15, today is 2026-05-15. Year difference is 36, but May is before June, so subtract 1 → 35 years. Remaining: from 2025-06-15 to 2026-05-15 = 11 months. Days: 0. Result = 35 years, 11 months, 0 days. Total days lived ≈ 13,118. Days until next birthday = 31.
Frequently asked questions
Does this handle leap years?
Yes. The calculation uses native date arithmetic which respects the Gregorian leap-year rules (every 4 years, except century years unless divisible by 400). Someone born on February 29 will see their 'next birthday' on March 1 in non-leap years.
Why is age different in different cultures?
Some East Asian traditions add a year at birth (you're 1 year old the day you're born) or count the lunar new year as a birthday. This calculator uses Western/Gregorian conventions — age 0 at birth, increment on each birthday.
Can I check age at a future or past date?
Yes. Change the 'as of' date to any value. Useful for figuring out when someone turns a specific age, or for legal questions like 'how old will I be on this contract end date?'
Is the time-of-day used?
Only date precision is used here. If you need hour-level precision (newborn medical records, astrology, etc.), use a date-time calculator instead.