It isn't inaccurate. Whether a certain BMI is healthy or not is debatable, but that isn't the same as whether the result is accurate or not.https://www.smartbmicalculator.com/_html/drop/rbch_03023.png
My BMI is 23.
Having 23 BMI almost definitely means I am a healthy weight. Mudderducker's comment is wrong, 23 is my BMI. It's completely accurate.
What it isn't is completely precise at deciding if someone is a healthy weight or not. Body builders tend to have high BMI's, but are not overweight whereas someone who weighed the same amount but was less muscular would be.
Edited 9/3/2018 15:32:49