I have a scale like that, but it is really inaccurate as it simply looks at your body composition based on your age, height and weight.
I use one of these
![](http://ep.yimg.com/ca/I/yhst-39130775443729_2225_226487911)
Once you figure out how to use it properly, it becomes fairly accurate .5-1% margin error, which is acceptable for me.