How we count your days
We count every calendar day from your date of birth to today in your own time zone, so leap days (29 February) are included automatically. Without a birth time we assume you were born at midnight; add it for exact hours, minutes and seconds.
Milestones are worked out the same way: your 10,000th day is the date exactly 10,000 days after your birth, and “1 billion seconds” arrives about 31 years and 8 months in.
Fun numbers, honestly labelled
Heartbeats, breaths and hours of sleep are estimates based on lifetime averages (about 80 beats and 16 breaths a minute, and roughly a third of your life asleep). Planet ages and the distance Earth has travelled are exact calculations.
Frequently asked questions
How many days old am I?
Enter your date of birth above and the calculator counts every calendar day since then, including leap days, using your device’s time zone. Add your time of birth for an exact count of hours, minutes and seconds.
When is my 10,000th day?
About 27 years and 4 months after you were born. The exact date depends on how many leap years you have lived through — the calculator shows yours, along with your 20,000th and 30,000th days.
How many days are in an 80-year life?
About 29,220 days (80 × 365.25). A 90-year life is about 32,870 days. Curious how many you probably have left? Try the death clock.
How accurate are the heartbeat and breath counts?
They are rough estimates using typical averages: about 80 heartbeats and 16 breaths a minute over a lifetime (both are faster in childhood). Your real numbers will differ, but the order of magnitude is right.
How is my age on other planets calculated?
We divide the days you have been alive by the length of each planet’s year: Mercury 88 Earth days, Venus 225, Mars 687, Jupiter 4,333 and Saturn 10,759.