For a 1 inch thick ribeye steak cooked in a skillet, cook for about 4-5 minutes per side for medium-rare doneness, or 5-6 minutes per side for medium doneness. The exact time may vary depending on the heat of your stove, the thickness of the steak, and your desired level of doneness. Remember to use a meat thermometer to ensure that the steak has reached your desired internal temperature before serving.