Learn how to calculate your exact age in years, months, weeks, and days — and what milestones like your 10,000th day alive look like.
Step-by-Step Guide
Enter your birth date
Open the Age Calculator tool and enter your date of birth in YYYY-MM-DD format. The tool instantly calculates your age as of today.
View age in multiple units
The calculator shows your age in years, months, weeks, and total days. You can also see hours, minutes, and seconds since birth.
Find milestone days
Fun milestones: your 10,000th day alive falls around age 27.4. Your 1,000th month alive is age 83.3. Try different birth dates to see when yours occur.
Calculate age for a future or past date
You can calculate how old you will be on any future date—useful for retirement planning, visa applications, or event scheduling.
Manual calculation
To do it manually: count the years, then add leftover months, then leftover days. Remember to account for leap years when counting day totals.
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Age Calculator
Frequently Asked Questions
Q: How do I account for leap years?
A: Leap years add an extra day every 4 years (except century years not divisible by 400). Our calculator handles this automatically.
Q: What is my age in months?
A: Multiply your years by 12, then add the number of months since your last birthday. Example: 25 years 3 months = 303 months.
Q: Why does age differ between countries?
A: Most countries count age at your last birthday. Some East Asian traditions count from 1 at birth (the "Korean age" system). Our calculator uses the standard international method.