Measure the size of the oven
 

Checking the size of the oven cavity sounds simple enough, however, this is where most people make mistakes

There are two methods we commonly use.

One is to measure the size of your existing oven and then look for a new oven of the same size. Of course, not only the length and width are important, but the depth as well - note that some ovens are not cubes, but are marked on the back.

The second option is to measure the oven cavity, especially moving the oven out of the cavity to check for any invisible power points or gas lines. If moving the oven, care should be taken not to break any existing connections.