Age Calculator
Enter a birth date and comparison date to find an exact calendar age, total days lived and the countdown to the next birthday.
Choose dates
Your dates stay on this device and are not submitted to our server.
Your age result
How the result is calculated
The exact age uses completed calendar years and months, then counts the remaining days. Total days uses the elapsed time between the two dates. For a February 29 birth date, this tool uses February 28 in non-leap years for the birthday countdown.
Age calculation example and limitations
Completed age is calculated by subtracting the birth year from the comparison year, then subtracting one when the birthday has not yet occurred in that comparison year.
Worked example
Someone born on October 20, 1990 is 35 years old on September 16, 2026 because the 2026 birthday has not yet occurred. The person turns 36 on October 20, 2026.
What the outputs mean
- Exact age shows completed calendar years, months and days.
- Total days lived counts elapsed calendar days between the selected dates.
- The birthday countdown finds the next occurrence after the comparison date.
Official age rules can differ for schools, insurance, benefits and legal deadlines. Use the relevant organization’s rules for formal decisions.