Most brands recommend a 2:1 ratio of ice to contents, although some suggest ⅔ ice to ⅓ goods. It is always best to follow the instructions in regards to ice capacity and adjust as you become more familiar with the product, depending on the type of ice (i.e. dry, blocked, cubed, or a combination of blocks and cubes). Keep in mind that the temperature of ice may vary, so keep your cooler in the shade or throw a tarp or towel over it to protect it from direct sunlight.