How to use the Age Calculator
Calculate completed calendar years, months, days, and total days from a birth date to a comparison date. Enter the requested values, review their units, and select Calculate. The result panel shows both the answer and the substituted steps.
The formula
age = comparison date − birth date, measured as calendar intervals
Frequently asked questions
How are months handled?
Calendar years and months use actual date boundaries rather than assuming every month has the same length.
Does a leap day affect total days?
Yes. Total elapsed days includes every leap day that falls within the interval.
Important notes
Results are estimates based on the values supplied and the formula shown. Round only at the end of a calculation, and verify safety-critical, medical, financial, or construction decisions with an appropriate professional.