AGE CALCULATOR GUIDE

How to calculate age from a date of birth

Calendar age is measured by comparing a date of birth with today or another reference date, then accounting for completed years, months, and days.

FORMULA

calendar age = completed years + completed months + remaining days

WORKED EXAMPLE

For a date of birth of 10 May 2000 and a reference date of 4 July 2026, the calculator counts completed calendar years first, then remaining months and days.

STEP BY STEP

Enter the date of birth

Use the exact day, month, and year whenever possible. The calculator does not need a time of day.

Choose today or another reference date

Keep today for a current age, or choose any later date when you need age on a specific day.

Read the calendar result

The result separates completed years, months, and days. It also shows totals and the timing of the next birthday.