To measure your sink base cabinet, all you really need is a tape measurer. First, you’ll want to measure the total depth of your cabinet, including the frame. You’ll want to measure front-to-back, and you simply place your tape measure on the bottom of the cabinet and place the other end of the tape against the back of the cabinet. Next, you’ll want to measure the width, and you do this by measuring the bottom of the cabinet and measure going from left to right. Lastly, you’ll want to measure the height, and to do this, you take the tape measure that’s still on the bottom, and you measure this going straight up to the top of your cabinet. After that, you can check the sink description to make sure it fits your cabinet. If it’s not specified, you can subtract three inches from the width of the cabinet and one inch from the depth to calculate the right size.