How old are you, exactly?

We compare your date and time of birth to the target date (today by default), walking forward year-by-year, then month-by-month, then day-by-day - accounting for leap years and varying month lengths. The result is the precise breakdown most people mean by "age."

Time of birth makes the day count exact down to the minute. If you were born at 23:59 yesterday, you're "one day old" only after that moment passes - not at midnight. Set 00:00 if you don't know your exact time.

They use medical averages - 80 beats and 16 breaths per minute - sustained over your full life so far. Real values vary with age, fitness, sleep, and activity. Treat them as a fun estimate, not a medical record.

We use the global average life expectancy of about 80 years as the baseline. The progress bar shows how much of that baseline you've lived. Life expectancy varies significantly by country, gender, and lifestyle - this is a rough reference, not a prediction.

Each planet's year is its orbital period in Earth days: Mercury 88, Venus 225, Mars 687, Jupiter 4,333, Saturn 10,759. Your total Earth days are divided by that number.

Useful when you need someone's age as of a specific date - legal forms, retirement planning, or "how old will I be on this date." Toggle it on and pick any date in the past or future.

No. Every calculation runs entirely in your browser. Your date of birth never leaves your device - no analytics on input fields, no cookies tied to your data, no cloud round-trip.

We use the Western calendar approximation: (year − 4) mod 12 maps to the 12 animals starting with Rat. The true Chinese New Year falls in late January or February - if you were born in January or early February, your traditional sign may be the previous year's animal.