Find your age today or on a date you choose. Enter a date of birth and a calculation date to see calendar years, months and days, plus the total number of days between them.
Age calculator
Calculated in your browser. No calculator values are submitted.
How to use the age calculator
- Enter the date of birth.
- Keep today as the calculation date, or select another date.
- Select Calculate. Change either date to compare another point in time.
How age is calculated
The calculator counts completed calendar years, then completed calendar months, then the remaining days. Total days is the exact difference between the two calendar dates; complete weeks equals total days divided by seven, with the remainder shown separately.
For example, someone born on June 15, 2000 is 25 years, 3 months and 5 days old on September 20, 2025.
Leap years and month ends
Months have different lengths. When an anniversary falls on a day that does not exist in that month, this calculator uses the last day of the month. A February 29 birthday therefore reaches its next calendar anniversary on February 28 in a non-leap year. Legal birthday rules can differ by jurisdiction; this tool is for date calculations, not a legal eligibility decision.
The calculation uses calendar dates rather than hours, so time zones and daylight-saving changes do not add or subtract a day. A calculation date before the birth date produces an error rather than a negative age.
