Age Calculator
Enter a date of birth to see your exact age today, or choose another date to see how old you'll be then.
Your details
Result
Fill in the fields to see your result.
Good to know: Your age is counted in whole years first, then months, then days.
About this tool
Calculate your exact age in years, months and days from a date of birth, plus total days, weeks and months lived.
Formula
Age = calendar difference from birth date to today, counting years first, then remaining months, then days (borrowing from the previous month when needed).
Reference values
- Leap years add 29 February into the count
- A month is counted from date to same date
- Total days ≈ years × 365.25
Questions people ask
How is age calculated?
Count whole years since the birth date, then the remaining months and days, borrowing days from the previous month when needed.
Can I calculate age at a future date?
Yes. Change the "Age at date" field.
Why do total days differ slightly from years × 365?
Leap years add an extra day about every four years.
Related tools
How we calculate this
We use the standard published formula or definition for this calculation, and we show the working so you can check it.
Spotted a mistake? Tell us and we'll check it. How we check our calculators