Age Calculator

How the Age Calculator works

Formula. Years are the difference in calendar years, then months and days are adjusted backward when the target month or day has not been reached. Total days are the timestamp difference divided by 86,400,000, and weeks are total days divided by 7.

Example. From January 1, 2000 to January 1, 2024 the year difference is 24, the month difference is 0, and the day difference is 0, so the age is 24 years, 0 months, and 0 days.

Limitation. The total-day count uses millisecond subtraction, so a daylight-saving transition between the dates can change that day count by one compared with a civil-date count.