Enter a birth date to see the exact age down to the day — the calculation runs entirely in your browser and no dates are ever uploaded.
Used automatically — no need to change anything.
Your age, every way
The same span of time, counted in different units.
*Rough estimates at ~72 heartbeats and ~16 breaths per minute, and about a third of life spent asleep.
Moments & milestones
Birthday countdown, your signs, and the next big round number.
How this age calculator works
Enter your date of birth and the tool shows your exact age in years, months and days, then keeps a live count of the seconds ticking by. It works entirely in your browser — your birthday never leaves your device.
Time zones, handled for you
Ages depend on where "now" is. The calculator auto-detects your device's time zone and uses it by default, so you don't have to do anything. If you were born in a different time zone and want to be precise to the hour, tick "Born in a different time zone" and pick it. Power users can also display their age as measured in any other zone — useful when a document needs your age at a specific location's local time.
Birth time is optional
Most people only need the date. If you know your time of birth (it's often on your birth certificate), add it for an age that's exact down to the second — otherwise midnight is assumed and the day-level age is still correct.
Two modes
"Age from birthday" is the everyday use. "Between two dates" measures any span — anniversaries, how long until a deadline, a notice period, or the gap between two events — and adds a working-days count that's handy for planning.
Frequently asked questions
How is my age calculated exactly?
We find the largest number of whole months from your birth date that doesn't pass today, then count the leftover days, hours, minutes and seconds. This handles leap years and different month lengths correctly, matching how you'd naturally count your age.
What happens if I was born on 29 February?
In non-leap years your birthday is treated as 28 February, so you still age a full year — the common legal and everyday convention.
Is my date of birth uploaded anywhere?
No. All calculation runs locally in your browser; nothing is sent to a server.
Why does the seconds counter move?
Because your age genuinely increases every moment — the live counter shows time passing in real time down to the microsecond.
How the calculation works
Your age isn't just this year minus your birth year. The tool checks whether your birthday has already happened this year, then counts the completed months and days against the real lengths of the calendar months in between. That's why it can say 25 one day and 26 the next, even though the year number hasn't changed.
Dividing the total elapsed days by 365 gets close, but it drifts. Leap years add a 29th of February, and the months you actually lived through weren't all the same length. Counting by the calendar keeps the result exact rather than approximate.
A worked example
Someone born on 10 June 2000 turns 26 on 10 June 2026 — exactly 26 completed years. On 9 June 2026, one day earlier, they are still 25 years, 11 months, and 30 days old. The single day is the difference between two whole-number ages, which a rough days-over-365 estimate would blur.
Calendar facts worth knowing
A common year has 365 days; a leap year has 366. The leap rule isn't simply "every four years" — a year divisible by 100 is not a leap year unless it's also divisible by 400. So 2000 was a leap year, but 1900 was not.
Because the months range from 28 to 31 days, "one month" is not a fixed number of days. Completed age and "year of life" also differ: a person who is 26 has already begun their 27th year of life.
Why calendars need leap years
A year is not exactly 365 days. The calendar periodically adds a leap day to keep calendar dates aligned with Earth's orbit. That is one reason a person's calendar age is better calculated from dates than by simply dividing elapsed days by 365.
Why months are awkward units
Months do not have a fixed number of days: modern calendar months contain 28, 29, 30 or 31. Age expressed as years, months and days therefore follows calendar boundaries rather than one constant conversion factor.