Age Calculator
How age is calculated
This calculator gives a detailed breakdown of your exact age from a birth date — not just "46 years old," but years, months, and days, plus how many total days, weeks, and hours you've been alive, and a countdown to your next birthday. You can also calculate age as of any other date, not just today, by changing the "As of date" field — useful for finding out how old someone was (or will be) on a specific date.
How to use it
Enter a birth date. The "As of date" defaults to today, but you can change it to any date on or after the birth date to see the age on that specific date instead. The result updates instantly with the full breakdown.
Example age calculation
Someone born January 1, 1980, as of today, is a specific number of years, months, and days old — plus tens of thousands of total days, thousands of weeks, and hundreds of thousands of hours lived, with a countdown showing exactly how many days remain until their next birthday.
Why exact age is more than current year minus birth year
Subtracting birth year from the current year gets you close, but it's wrong for roughly a third of the year — anyone whose birthday hasn't happened yet this year is actually one year younger than that simple subtraction suggests. This calculator instead compares the full birth date to the "as of" date, so the years, months, and days it reports are always exactly correct, not just approximately right.
Additional age measurements
Beyond the years/months/days breakdown, the result also shows your total time alive in three other units — days, weeks, and hours — plus a countdown to your next birthday from whichever "as of" date you've selected. These aren't separate calculations; they're the same span of time expressed a few different ways, useful for anything from a fun fact to a form that specifically asks for age in days.
Common use cases
- Finding your exact age in years, months, and days, not just a rounded number
- Calculating how old someone was, or will be, on a specific date
- Counting down the days until your next birthday
- Finding a fun fact like your total days, weeks, or hours lived
Frequently asked questions
How old am I exactly?
Enter your birth date — the result shows your age as years, months, and days, not just a single rounded number.
How do I calculate age from a date of birth?
Enter the birth date; the "As of date" defaults to today, or you can change it to see the age on any other date.
How many days old am I?
The result includes a full breakdown — total days, weeks, and hours alive, alongside the years/months/days figure.
How long until my next birthday?
The result includes a countdown showing exactly how many days remain until the next birthday from the "As of date."