Enter a birthdate and get an exact age in years, months, and days — plus the totals in months, weeks, days, and hours, and a countdown to the next birthday. There’s also an “age at this date” field for checking age on any specific day: school cutoffs, application deadlines, or historical dates.
How the math works
The calculator is calendar-aware, not a rough division. It counts actual years, months, and days the way you would by hand: full years first, then full months, then the leftover days — borrowing from the previous month’s real length when the day-of-month doesn’t fit. That’s why someone born January 31 is exactly one month old on February 28 in a common year, and why a February 29 birthday still gets an accurate, sensible age every year.
What the numbers mean
The headline number is the “official” age used for forms, school enrollment, sports leagues, and legal cutoffs. The totals underneath answer different questions — total days lived is handy for “10,000 days” milestones, total weeks and months for development tracking or countdowns. The next-birthday line shows the exact date, the weekday it lands on, and how many days remain, so leap-year birthdays and weekend parties stop being a puzzle.
To check age on a specific date instead of today, set the “age at this date” field to that day — say, a school enrollment cutoff or January 1 of a given year. Everything runs locally in your browser: no accounts, no tracking, and the dates you enter never leave your device.