Age Calculator
Find your exact age in years, months, and days, plus your total days lived and time until your next birthday.
Years
—
Months
—
Days
—
Total Days Lived
—
Next Birthday In
—
Day of the Week Born
—
Total Weeks Lived
—
How Age Is Calculated
This calculator finds the exact difference between your date of birth and the reference date, then breaks that span down into complete years, remaining months, and remaining days, rather than a rough estimate based on 365 days per year.
Because calendar months vary in length and leap years add an extra day every four years, this method gives a more accurate result than simply dividing total days by 365.
Total days lived, total weeks lived, and the countdown to your next birthday are all derived from the same date difference, giving a fuller picture beyond a single age number.
How to Use This Age Calculator
Enter your date of birth.
The “as of” date defaults to today, but you can change it to calculate age on any past or future date.
Your exact age, total days lived, and next birthday countdown appear instantly.
Frequently Asked Questions
How is age calculated so precisely?
The calculator compares full calendar dates, accounting for the actual number of days in each month and leap years, rather than assuming every year has exactly 365 days.
Can I calculate someone’s age on a future date?
Yes, set the “Calculate age as of” field to any future date to see what someone’s age will be on that day.
Why does my age in months not match years multiplied by twelve?
The months shown are the remaining whole months after full years are subtracted, not a running total, so it always fits with the years and days shown alongside it.
Is my birth date stored anywhere?
No, the calculation happens entirely in your browser and nothing you enter is saved or transmitted.