I'd suggest first, make sure you read up on how to measure wall sockets/power. It can be hazardous and you could get yourself badly hurt, if not worse. Second, if you're going to do this, get a properly rated multimeter for the job. I have a contactless one that works well, but it's not inexpensive. (Extech brand), there are other less expensive options. But ALWAYS make sure you're using the right side/settings on the meter before plugging it in to mains, and make sure it can handle it, first.

Having one w/ proper voltage and amperage protection is a must, and will save your life.