How to Use a Shim to Level a Microwave Oven

Check the microwave so there is nothing under it that might be causing it to sit unevenly. It is possible that something has rolled under one corner and become stuck there, causing the appliance to sit at a slight angle even though the surface is even. If this is the problem, simply removing the object will most likely resolve the problem.

Place the bubble level on top of the microwave oven, with the ends pointing left and right. The bubble will float out of the marked center area of the level, indicating that the microwave is slanted to one side or the other. If the bubble is centered, indicating that the microwave is level from side to side, turn the level 90 degrees, and check it from front to back. A microwave that is not level will either show a problem from side to side or front to back -- and possibly in both directions.

Push a shim under the lowest corner of the microwave. Do it gently so you don’t accidentally move the entire microwave; if it moves, you will need to begin the entire process again. Continue pushing the shim into place until it feels solid so that it won’t slip out of position on its own. The bubble in the level will move until it is centered between the two marks in the viewing window, indicating that the microwave is now level. If the shim doesn’t level the microwave, remove it and try again with a thicker shim. In some cases, you may need to use more than one shim to get the microwave level.