Age Calculator
Find your exact age in years, months, and days, then count down to your next birthday, your next decade milestone, and your retirement date. Correctly handles February 29 (leap day) birthdays. Everything runs privately in your browser.
How to use the Age Calculator
Enter your date of birth and, if you'd like a personalized retirement countdown, your target retirement age (it defaults to 65). Click Calculate My Age to instantly see your exact age in years, months, and days, plus countdowns to your next birthday, your next decade milestone (30, 40, 50, and so on), and your retirement date.
If you were born on February 29, the calculator automatically flags your leap-day birthday and observes it on February 28 in years that aren't leap years, so every countdown still lands on the right day.
How is exact age calculated?
Your exact age is found by subtracting your date of birth from today's date, then breaking the difference into whole years, whole months, and remaining days:
Milestone countdowns work the same way in reverse: the calculator finds how many years, months, and days remain between today and the target date — your next birthday, your next decade birthday, or the date you reach your chosen retirement age.
Frequently Asked Questions
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How is exact age calculated?
Exact age is calculated by finding the difference between your date of birth and today's date, broken into years, months, and days. Whole years are counted first, then the remaining months, then the remaining days — the same method used on birth certificates and legal documents.
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How does the calculator handle people born on February 29?
People born on February 29 (leap day) only have a true birthday once every four years. In non-leap years, this calculator observes the birthday on February 28, which is the most common convention, so birthday and milestone countdowns still work correctly every year.
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How is the next decade milestone calculated?
The calculator finds the next age that is a multiple of ten — 30, 40, 50, and so on — that is greater than your current age, then counts down to that birthday.
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Can I change the retirement age used in the countdown?
Yes — enter any retirement age you like. The calculator defaults to 65, a common retirement benchmark, but you can set it to match your own pension plan, country, or personal goal.
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Is my date of birth stored or sent anywhere?
No — all calculations run entirely in your browser using JavaScript. Your date of birth is never transmitted to or stored on any server. See our Privacy Policy for details.