Birthday Age Calculator
Find out exactly how old you are on your birthday or any date. Perfect for celebrating milestones.
How to Calculate Age
Birthday calculation: See your age in years, months, weeks, and total days lived
Methodology
Calculating age isn't simply subtracting birth year from current year. The number of days in months varies (28, 30, or 31), and leap years occur every 4 years (adding a 29th day to February).
Leap Years
A year is a leap year if divisible by 4, except century years must be divisible by 400. This calculator automatically accounts for leap days.
Age Facts
- 1 year = 365.25 days (average)
- 1 year = 52.18 weeks
- 1 year = 12 months
- 10 years = 1 decade
- 100 years = 1 century
Frequently Asked Questions
Can I calculate my age on a specific birthday?
Yes, this calculator shows your exact age from birth to today. For a specific date, use our Date Difference calculator.
How many days until my next birthday?
After calculating your age, subtract from your next birthday year to find remaining days.