Age Calculator
Find your exact age in years, months and days, total days lived, and a countdown to your next birthday.
How exact age is calculated
This tool doesn't just divide the number of days by 365 — that produces a slightly wrong answer because of leap years and months with different lengths. Instead it does calendar subtraction, the same way you'd count on your fingers: it takes the years, months and days between your two dates and "borrows" from the next unit whenever a subtraction would go negative, exactly like borrowing in long subtraction. That gives you the precise, calendar-accurate age a government form or ID would expect.
Frequently asked questions
How is my exact age in years, months and days calculated?
By calendar subtraction between your birth date and the target date, the same way you'd count by hand — borrowing a month or year whenever the day or month subtraction goes negative. This is more accurate than dividing total days by 365, which ignores leap years and variable month lengths.
Can I calculate someone's age on a past or future date, not just today?
Yes — change the "Age as of" field to any date, past or future, to see what someone's age was or will be on that date.
How many days until my next birthday?
The calculator finds the next occurrence of your birth month and day from the "as of" date and counts the days remaining, shown in the results grid.
Is my birth date stored or sent anywhere?
No. The date fields are read directly by JavaScript in your browser and never transmitted to any server.