Everyone has one. Even dogs have one. I’m talking about date of birth. In this video you’ll learn how to calculate age from the date of birth using DATEDIF, a super-secret Excel function, so secret that it doesn’t appear in Excel’s Functions drop-down list!

So whether you need to calculate the age of a person in whole years or the age of a puppy in weeks, check out this short video. Links to the video and individual sections below…

Use the DATEDIF Function to Calculate Age in Years

Use the DATEDIF Function to Calculate Age in Weeks

Use the INT Function to Fix the Rounding Problem