I have found that there are a couple of ways to check the wattage of
your plugs.  You can use a Circuit tester, or a Multimeter. 

 I have never used a Circuit Tester, it looks super easy and there is a picture of
what the different lights mean, and a button to do a Ground Fault Circuit test.
There is no way for you to electrocute yourself if you use this device. 

I used a Multimeter which is so old fashion. The first thing is that you have to
make sure you know all the parts to the multimeter  There
are two extensions that come out. One is black and is called the Ground. The
other is red and is called the Lead. Next you have the display that shows you
the voltage. Then you have the dial on the right left side is the DC volts and
on the right is the AC volts. You cannot be shocked with this device either
since you are touching the plastic.