Age in Years, Months, and Days Calculator

Enter your date of birth and an optional as-of date to find your exact age broken down into years, months, and days. The Age in Years, Months, and Days Calculator also shows your total age in months, weeks, and days so you get the full picture at a glance.

Enter the date of birth you want to calculate age for.

Leave blank to use today's date, or enter a past/future date.

Results

Exact Age

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Years

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Months (remainder)

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Days (remainder)

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Total Months

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Total Weeks

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Total Days

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Frequently Asked Questions

How do I calculate age in years, months, and days?

To calculate age precisely, subtract the birth year, month, and day from the target date separately. If the day or month differences are negative, borrow from the higher unit (e.g., borrow a month's worth of days). This gives you the exact number of complete years, remaining months, and remaining days since birth.

What is my age if I was born in 1998?

If you were born in 1998, you are either 26 or 27 years old in 2025, depending on whether your birthday has occurred yet this year. Use this calculator with your exact birth date to get your precise age in years, months, and days.

Can I calculate how old someone will be on a future date?

Yes — simply enter the person's date of birth and set the 'Age As Of Date' field to any future date. The calculator will tell you exactly how old they will be on that day in years, months, and days.

How old is my child in months?

Enter your child's date of birth and leave the 'Age As Of Date' as today. The calculator displays the total number of months your child has been alive, which is especially useful for tracking infant development milestones.

How many days have I been alive?

The calculator shows your total number of days lived under the 'Total Days' output. It accounts for leap years so the count is accurate regardless of when you were born.

How does age calculation handle leap years?

This calculator uses JavaScript's native Date object, which correctly handles leap years (366-day years). The total weeks and total days figures are therefore accurate even if your lifespan spans multiple February 29ths.

Can I find someone's age at a past event, like a marriage or graduation?

Absolutely. Enter the person's date of birth and set the 'Age As Of Date' to the date of the event. The result shows exactly how old they were at that moment in years, months, and days.

Why is my age shown differently in some cultures?

Different cultures count age differently. The most common Western system increases age on each birthday. Some East Asian traditions count a person as age 1 at birth and add a year at the new year. This calculator uses the standard Western birthday-based system.

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