Age Calculator

How old are you, exactly — down to the day? Enter a date of birth and this calculator gives the precise age in years, months and days, plus total days lived, your birth weekday, and the countdown to the next birthday.

Results

Formula

Age is counted in completed years, then completed months, then days — borrowing days from the previous month when needed, the same convention used on official documents:
Age = (Years, Months, Days) elapsed since the birth date

How to use this calculator

  1. Enter the date of birth.
  2. Leave “as of” empty for today, or pick any other date.
  3. Press Calculate for the exact breakdown.
Age Calculator — how the calculation works, illustrated
Age Calculator — how the calculation works, illustrated

Worked example

Born June 15, 1990; age on November 7, 2026.

  1. Completed years: 36 (birthday passed in June).
  2. Months since June: 4, plus 23 days into the next month.
  3. Total days lived: 13,294.

Result: The exact age is 36 years, 4 months, 23 days.

Frequently asked questions

How is age calculated for someone born on February 29?

In non-leap years their legal birthday is usually observed on February 28 or March 1 depending on jurisdiction. This calculator rolls the next-birthday date to February 28 in non-leap years.

Why do some cultures count age differently?

Traditional East Asian reckoning counts a newborn as 1 and adds a year each New Year. The calculator uses the Western completed-years system used on US and European documents.

Can I calculate the age of a building or a pet?

Yes — any start date works. For pets in human-equivalent years, use the dedicated Cat Age Calculator, which applies a veterinary aging model.

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