there are a lot of body fat calculators online - that really aren't accurate -however, if you use them consistently and do what you are supposed to do consistently you will see the numbers change.
Most gyms will have a handheld device that your age/height/weight/gender get entered into and it sends signals thru your body to get an estimate- again not totally accurate but you will see changes with constant use.
Calipers you can get online - and do your own measurements -there's alittle learning curve in how to use them... but they're probably more accurate than anything else