Age Calculator

The Age Calculator determines a person's exact age from their date of birth, breaking it down precisely into years, months, and days rather than rounding to a single whole number. It works by comparing the birth date against a target date (today by default) and accounting for the varying lengths of months and for leap years, so February birthdays and end-of-month dates resolve correctly.

Internally the calculation borrows days from the preceding month when the target day is earlier than the birth day, then borrows a month when the resulting month count goes negative, mirroring how you would subtract dates by hand. This is more accurate than dividing total elapsed days by 365.25, which drifts over long spans. The result reflects calendar reality, the same way official age is reckoned for legal and medical purposes.

Common uses include verifying eligibility thresholds (voting, driving, retirement), filling out forms that ask for age in years and months, tracking an infant's age in weeks and days, and satisfying simple curiosity about milestone birthdays. Many people also use it to compute age as of a future or past date by changing the target field.

For the most reliable result, enter the date of birth using the calendar picker to avoid ambiguous formats, and double-check the target date if you need age as of a specific event rather than today. If you want to compare two people instead of one person against today, the Age Difference tool is the better fit, and the Birthday Calculator tells you how long until the next birthday.