How to Determine Microwave Oven Size

Microwave size is determined by the cubic feet of the oven's interior cavity. A small microwave will measure less than 1 cubic foot; larger microwaves can measure 2 cubic feet or more. Knowing your microwave's size will help you determine whether you can cook large items, such as a whole chicken or turkey.

turn on microwave oven
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Hand turning knob on microwave oven.

Step 1

Open the door of your microwave and measure the length, width and height in inches of the interior cavity.

Step 2

Multiply the length by the width by the height using a calculator to get the total in cubic inches.

Step 3

Divide the cubic inches by 1,728, which is the volume of a cubic foot. The resulting number will be your microwave's measurement in cubic feet. You can also use an online conversion calculator to simplify matters.