Age Calculator

The Age Calculator works out an exact age from a date of birth, broken down into years, months and days, along with totals in months, weeks and days lived, and a countdown to the next birthday. It answers the everyday 'how old am I' question with more precision than mental math — instead of just counting birthday years, it shows exactly how many months and days have passed since the last one.

By default the calculator measures age as of today, but you can set any custom 'age at' date instead, which is useful for questions the default view can't answer: how old someone was on the day a document was signed, how old a child will be on the first day of school, or what age a person turns on a specific future event date. This makes it just as useful to calculate age from a date of birth for a past reference point as for right now.

The math is based on real calendar months and actual leap years rather than a rough 30-day-per-month approximation, so the result matches how age is counted legally and on official forms: someone born on January 31 turns one month old on the last day of February, and someone born on February 29 in a leap year still has their age tracked correctly against non-leap-year anniversaries.

It's a small tool with a lot of everyday uses — filling out applications that ask for exact age, checking eligibility cutoffs tied to a specific birthdate, planning a birthday countdown, or just settling a curious 'how old am I really, down to the day' question. Everything is calculated instantly in your browser and nothing about your date of birth is stored or transmitted anywhere.