Age Calculator
Find your exact age in years, months, weeks, and days — plus how many days until your next birthday.
About This Age Calculator
This free age calculator tells you your exact age down to the day — not just the year. Enter your date of birth and the calculator works out your precise age in years, months, weeks, days, and hours. You can also change the “as of” date to calculate someone’s age on a specific past or future date, which is useful for everything from filling out forms to planning milestone birthdays.
What This Calculator Shows You
Enter your date of birth and get your exact age in years, months, and days, your total lifespan expressed in months, weeks, days, and hours, how many days remain until your next birthday, and fun life estimates including heartbeats, meals, and nights of sleep.
How Age Is Calculated
Age calculation is more nuanced than it looks. The calculator counts full calendar years first, then full months, then remaining days — the same method used on official documents. For example, someone born on March 31 turns one year older on March 31, regardless of the month length. Leap years are handled correctly: someone born on February 29 celebrates their birthday on February 28 in non-leap years.
When to Use the “As Of” Date
The default “as of” date is today. Change it to calculate age on a specific date — for example, how old you were on your graduation day, how old a child will be when they start school, or the exact age of a historical figure on a significant date. The tool works just as accurately for future dates as it does for the past.