Age Calculator — Find Your Exact Age in Years, Months, Days
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Enter a date of birth to find the exact age in years, months, and days. You can also set a custom reference date to calculate age at any point in time. The calculator also shows your total days lived, how many days until your next birthday, and which day of the week you were born. All calculations run in your browser — nothing is sent anywhere.
How it works
- 1 Enter your date of birth Click the date field and pick your birthdate from the calendar, or type it in YYYY-MM-DD format. The result appears immediately.
- 2 Adjust the reference date (optional) The 'Age as of' field defaults to today. Change it to calculate your age at any past or future date — useful for anniversary calculations or historical lookups.
- 3 Read the results Your age appears in years, months, and days. Below that: total days lived, days until your next birthday, and the weekday you were born.
Your data stays private
All processing happens entirely in your browser. No files, text, or data are ever sent to our servers. You can disconnect from the internet and this tool will still work.
Frequently asked questions
- How is the exact age calculated?
- The calculator counts complete years, then complete months within the remaining period, then the remaining days. For example, someone born on May 15, 1990 is exactly 36 years, 0 months, and 7 days old on May 22, 2026.
- What happens with leap day birthdays (February 29)?
- In non-leap years, February 29 birthdays are treated as February 28 for the monthly anniversary. So on February 28 of any non-leap year, a leap-day birthday person completes a full year (or month).
- Can I calculate the age between two specific dates?
- Yes. Fill in any birthdate in the first field and any target date in the 'Age as of' field. The calculator works for any two dates — past, present, or future.
- How is 'total days lived' calculated?
- It is the exact number of calendar days between the birthdate and the reference date, inclusive of the start date. Leap years are accounted for automatically.
- Is the next birthday countdown accurate for leap day birthdays?
- The next birthday is always set to February 28 in non-leap years and February 29 in leap years, so the countdown is accurate regardless of birth year.
- Is this calculator private?
- Yes. All calculations run entirely inside your browser using JavaScript. Your birthdate is never sent to a server, stored, or shared with anyone.