"The body fat scales you can buy online are safe and convenient, but they aren't accurate," says Dr. Woolcott, who adds that studies on these devices aren't reliable because they're tested on a small number of people. "The scales underestimate or overestimate body fat percentage by quite a lot.

Do BMI scales actually work?

Body fat scales are not very accurate at estimating a person's body fat percentage. However, they may provide a rough idea of how much fat a person has in their body. Together, body fat scales and BMI can give a general indication of a person's health.

Is the BMI scale inaccurate?

BMI is not an accurate predictor of health because it does not account for body fat percentage or body fat distribution. ... Measurements that are more accurate than BMI at predicting health outcomes include blood pressure, waist circumference, and cholesterol levels.