Calculate exact age in years, months, and days from a birth date.
This calculates exact age in years, months, and days between a birth date and another date (defaulting to today), accounting correctly for varying month lengths and leap years — the kind of date arithmetic that's easy to get subtly wrong doing it by hand or with a rough "divide by 365" estimate.
Beyond the headline age, it also shows the total in days and weeks, and the number of days remaining until the next birthday — useful for eligibility checks (many age-based cutoffs, like school admission or a competition category, care about the exact date, not just the year).
Worked example: someone born June 15, 2000, as of March 10, 2026, is 25 years, 8 months, and 23 days old — not 26 years, since their birthday this year hasn't happened yet. The trickiest part by hand is "borrowing": when the current day-of-month falls before the birth day-of-month (here, the 10th falls before the 15th), that month hasn't fully completed yet, so a month gets borrowed from the year count before the day difference is worked out — the same idea as borrowing in subtraction, just applied to a calendar instead of digits.
Everything is computed locally in your browser from the two dates you enter; nothing is sent anywhere.
Yes — it calculates using actual calendar dates, not a fixed 365-day average, so leap years are handled correctly.
Yes — set the "as of" date to any date, useful for checking age eligibility as of a specific cutoff or deadline rather than the current date.
No — the calculation happens entirely in your browser and nothing is sent to a server or saved anywhere.