Defaults to today.
- Total months
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- Total weeks
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- Total days
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- Total hours
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Enter your date of birth to find out exactly how old you are, or how old someone will be on any date. The age calculator handles leap years and month lengths correctly.
How to use the Age Calculator
- 1 Enter the date of birth.
- 2 Leave the second date as today, or choose any past or future date.
- 3 See the exact age, running totals and the next birthday.
Formula
Age = whole months from the birth date to the target date (as years + months)
+ the remaining days after the last whole month
Worked examples
Input: Born 15 June 1990, on 3 October 2026
Result: 36 years, 3 months, 18 days
13,259 days in total
How exact age is calculated
The calculator counts complete calendar months between the two dates, converts them to years and months, and then counts the leftover days. This matches how people normally state age and avoids the errors of dividing total days by 365.25.
Leap-year birthdays
If you were born on 29 February, your birthday in common years is treated as 28 February — the convention used by many legal systems. Some countries use 1 March instead.
Chronological vs. biological age
This tool calculates chronological age — time elapsed since birth. "Biological age" estimates from fitness tests or blood markers are a different concept.
Frequently asked questions
How do I calculate my age in days?
Enter your date of birth — the "Total days" box shows the exact number of days you have been alive.
Can I calculate age on a future date?
Yes. Change the second date to any date to see how old you will be then.
Does this account for leap years?
Yes. All calculations use the real calendar, including leap days.
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Leap Year Checker
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