Age calculator
Enter a date of birth and comparison date to calculate age in years, months and days.
Calculate age
What the age calculator shows
The age calculator compares a date of birth with a selected calculation date. It returns calendar age in full years, then the remaining months and days after the last full year and month.
How to use the calculator
Enter the date of birth and check the calculation date. Today is filled in by default, but you can choose another date to see the age at that point in time.
How the age is calculated
The calculation starts from the date of birth and counts complete calendar years to the comparison date. If the birthday has not yet occurred in the comparison year, the number of full years is one lower.
After that, the calculator counts complete calendar months and the remaining days. The result is based on calendar dates rather than fixed average month lengths.
Example calculations
- Date of birth 1 January 2000 and calculation date 1 January 2026 gives 26 years, 0 months and 0 days.
- Date of birth 1 June 2000 and calculation date 1 January 2026 gives 25 years, 7 months and 0 days.
- Date of birth 15 April 2000 and calculation date 29 April 2026 gives 26 years, 0 months and 14 days.
Years, months and days explained
Years are complete calendar years between the two dates. Months are counted after the last full year, and days are counted after the last full month. This keeps the result tied to real calendar dates instead of converting everything through an average month length.
Leap years and calendar dates
The calculator uses calendar dates and browser date handling. Different month lengths and leap years are part of that practical calendar calculation, but the result is only the age at the selected calculation date.
Limitations
Use the result as a practical calendar calculation. The calculator does not decide legal age limits, contracts, official decisions or identity-related questions. For formal situations, check the relevant source or ask a qualified professional.
Frequently asked questions
Can I choose the calculation date?
Yes. Use today for current age, or choose another date to calculate age at that point in time.
Can the date of birth be after the calculation date?
No. In that case the calculator shows an error message instead of an age result.
What result does the tool show?
It shows age in years, months and days at the selected calculation date.
How are leap years handled?
The calculation uses calendar dates, so different month lengths and leap years are reflected in the calendar result.
Can this be used for official age limits?
Treat it as a practical date calculation. Legal age limits, contracts and official decisions may require checking the relevant rule or authority.