The scale told me I was very close to my college weight but I just knew I didn't look like my college self. Just on a lark I placed some weights on my bathroom scale and found that it is about 1 - 4 lbs off. It is about 20 years old so it is time for a new scale.

Do the ones that read the body fat percentage really work? How do they work?

Any tips for checking that the scale is working correctly, besides just placing weights on it from time to time?

You might find this site of interest. They make BF% scales http://www.tanita.com/IndexUS.shtml

Here's how they work:
http://www.tanita.com/HowBIAworks.shtml

The only way I've found to check is to go to a Dr. office and go directly home and check again

I got a Tanita digital for fathers day. It is very good but I don't use the body fat % stuff. My old scale was off by 8 pounds!

Most folks are disapointed with the accuracy of the body fat % from any scales.

I have a Tanita BC532.

I can see why people would think the body fat calculation was highly inaccurate. It bugged me to begin with.

The scales are VERY dependent on getting an accurate water content reading. If you weigh in the morning you are dehydrated, as the day goes on more and more hydrated. If you are salt-sensitive, like me, it's an even bigger problem.

In addition water and food just eaten (or about to depart if you know what I mean) counts as weight but not fluid and can also skew the figures.

So as recommended by Tanita late in the day before your main meal is the most accurate time to weigh.

I like to know EXACTLY what's going on in my body, having just come off a load of meds for long term health problems. I'm of the view that I'm the one that takes responsibilty for my health, so for a while I'm putting in a lot of effort and I weigh twice a day. But that's just me - it helps me know how I'm responding to sodium etc..

Morning weights are lower than evening weights but evening weighings are more consistent when comparing one day or week to the next. I know a lot of people will say don't weigh more than once a week but I feel it gives a better feel for which figures I can trust and which might be affected by water.

If you decide to get a body fat scale, get one with water% on it as this will help you weed out any inaccuracies, ie high water will show an innacurate lower fat%.

Hope this helps a little. And I do love my sclaes - it's just a question of understanding how they work and knowing their limitation.

I agree with Gay, only want to add that to solve the water% problem I drink a lot on the afternoon and don't drink or eat one hour before weighing (when coming home from work). This way I hope to achieve to be always maximal hydrated for consistency.

These day's I don't weigh anymore every day, but in the beginning I did. I just wanted to be sure to move in the right direction. I plotted a 7 or 10 day moving average of the numbers, so you get in the graph a much better view by ruling out any daily differences.