Age Calculator
Find exact age in years, months and days — plus a countdown to the next birthday.
About this age calculator
Your age in years is easy; your exact age in years, months and days is not, because months have different lengths and leap years add an extra day. This calculator handles the calendar for you and also shows your age in total months, weeks and days, the weekday you were born, and how many days remain until your next birthday.
You can also calculate age on any date — useful for eligibility rules, school enrollment cut-offs, insurance forms or the age of a document, pet or anniversary.
How to use the Age Calculator
- Enter the date of birth.
- Leave the second date as today, or choose another date.
- Read the exact age and the extra details.
How exact age is calculated
The calculator subtracts years, then months, then days. If the day of the month hasn't been reached yet, it borrows the number of days in the previous month; if the month hasn't been reached, it borrows 12 months from the years. People born on February 29 are treated as having their birthday on March 1 in non-leap years.
Worked example
Someone born on May 15, 1990 is 36 years, 4 months and 29 days old on October 14, 2026 — 13,301 days in total.
Tips for better results
- For legal deadlines, check whether the rule counts a birthday as reached at the start of the day (most US rules do).
Frequently asked questions
How do I calculate my exact age?
Subtract your birth date from today in years, then months, then days, borrowing days from the previous month when needed. This calculator does it automatically.
How are leap-year birthdays handled?
If you were born on February 29, your birthday is counted as March 1 in years without a February 29.
Last reviewed: October 2026 · Results are calculated in your browser.