Age Calculator

Enter your date of birth to find your exact age in years, months, and days.

Your Exact Age

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How to Use This Age Calculator

Whether you're filling out a form that needs your exact age or just curious how many days you've been alive, this calculator gets you the answer in seconds. Follow the steps below to get started.

Step-by-Step Guide

1

Enter Your Date of Birth

Use the date field to type or select the day, month, and year you were born. Double check the year, it's the easiest field to get wrong.

2

Choose a Reference Date

By default the calculator uses today's date. If you want your age on a different day, such as a deadline or an event, swap in that date instead.

3

Click Calculate

Hit the calculate button and your age appears instantly, broken down into years, months, weeks, days, hours, and seconds.

4

Read the Full Breakdown

Scroll through the results to see every unit at once, so you don't have to run the calculation again if you need your age in a different format.

5

Toggle Korean Age (Optional)

Flip on the Korean age switch if you also want to see your age under the traditional counting system, where everyone turns a year older on January 1.

Chronological vs. Biological Age

There's a difference between the age on your ID and the age your body might "feel" biologically:

Birth Date → Today's Date = Chronological Age
  • Chronological age is the calendar-based age this calculator gives you. It's what appears on every legal and medical document.
  • Biological age reflects how well your body is aging based on fitness and health markers, and can be higher or lower than your actual age.

Only chronological age has any legal standing, which is exactly what this tool calculates.

Why Leap Years Matter Here

If you were born on February 29, your birthday only comes around once every four years. This calculator automatically uses February 28 as your anniversary in ordinary years, so your age never drifts off by a day.

Frequently Asked Questions

Answers to the most common questions people have about calculating age.

It uses exact calendar day arithmetic rather than rounded averages, and it accounts for leap years correctly, including the century exception rule. The result is precise enough for medical, legal, or administrative use.

Some tools treat every month as a flat 30 days to simplify the math. This calculator counts real calendar months instead, so the numbers can come out slightly different, especially around February.

Yes. Change the reference date field to any past or future date and your age will be recalculated as of that day instead of today.

In years without a February 29, the calculator treats February 28 as your birthday. Once a leap year comes around again, it switches back to the real date.

No. All the calculations run directly in your browser. Nothing you enter is sent to a server or saved anywhere.

Not directly through this tool, but the logic is simple: subtract the age from the reference date to estimate the birth year, then adjust depending on whether the birthday has already passed.

Years equal the current year minus your birth year, reduced by one if your birthday hasn't happened yet this year. The remaining months and days are worked out afterward using the actual length of each month rather than an average. It's the same result you'd get from a spreadsheet using DATEDIF for years, months, and days separately.