Exact Age Calculator
Calculate live exact age from date and optional time of birth, with years, months, days, hours, minutes, seconds and total time lived.
If you do not know the exact birth time, 00:00 may be off by up to 24 hours; use 12:00 as a midpoint estimate.
Live exact age with time of birth
Exact-age searches usually want a live breakdown: years, months, days, hours, minutes and seconds from a birth date and optional birth time.
t_age is elapsed time, t_now is the current browser time, and t_birth is the entered local birth date and time.
Precision and supporting totals
- Unknown birth time limits precision; 00:00 may be off by up to 24 hours, while 12:00 can be used as a midpoint estimate.
- Total days, weeks, hours, minutes and seconds are supporting units.
- Heartbeat, breath and sleep-hour values are rough lifestyle estimates, not medical facts.
- The live display uses the browser's local time zone and updates every second.
Frequently Asked Questions
Sources and References
- DateMDN Web Docs
- Representing dates and timesMDN Web Docs
- Gregorian calendarBritannica
- ISO 8601 date and time formatISO
- International System of Units: TimeNIST
Calculations are based on the listed reference sources. Links open in a new tab.
Related Tools
Calculate exact chronological age from a date of birth to today or any as-of date, with years, months, days and total-day breakdowns.
Calculate how many full days you have lived from a birth date or event date, with weeks, hours, seconds and day-milestone dates.
Calculate the number of days between two dates, with exclusive or inclusive counting, weeks, calendar years/months/days and weekday/weekend totals.
Count how many calendar days are left until an event or how many days have passed since it, with weeks, months, weekday and rough weekday totals.
Find the weekday for any date, including birth dates and future dates, with ISO day number, ISO week-year, day of year, weekend status and leap-year context.