Age Calculator

Age looks like a single number, but it is really the difference between two dates, and the interesting part is how that difference is expressed. This calculator gives your age in years, months and days — the form used on forms and passports — alongside the totals in days, weeks and hours, and a countdown to your next birthday.

The years-months-days form requires care because months have different lengths. The standard method compares the two dates component by component: subtract the day numbers, borrow a month if the result is negative, then subtract the month numbers, borrow a year if needed, and finally subtract the years. That is why a person born on the 31st can appear a day or two different from a naive subtraction in months with fewer days.

The totals are simpler. The number of days between two dates is their difference in the underlying day count, which accounts for leap years automatically. Weeks are days divided by seven, and hours multiply days by twenty-four. These totals are the figures that matter for milestone calculations: eligibility windows, visa periods, interest accrual, or any rule written in days rather than years.

Leap years are the subtlety in any date arithmetic. A leap day is added roughly every four years, with century exceptions, and it affects both the total day count and the age calculation for anyone born on 29 February. This calculator handles the standard Gregorian rules, but the exact convention for a February 29 birthday varies by jurisdiction, so confirm anything legally significant.

This calculator is an educational estimator. It is not financial, medical, tax, or legal advice, and it does not account for fees, local rules, or your personal circumstances. Confirm decisions with a qualified professional.