Measure the water. Most rice cooker instructions recommend cold water.[4] How much water you add depends on what kind of rice you're cooking and how moist you prefer it. One rule of thumb is to fill the cooking pot with the same amount of cups of rice you used, with an additional 1/2 cup. For example, if you made 2 cups of rice, pour in 2 1/2 cups of water. There are also graduated marks on the inside of many rice cookers indicating how much rice and water should be added. The USA Rice Federation[3] recommends following the directions on the package that the rice came in, or using these guidelines in a pinch: