Water Calculator : The human body requires a fresh supply of water every day. Not only is water one of the most abundant nutrients available, but it's also the most important. Water helps regulate and maintain your body temperature, transports nutrients and oxygen, removes waste products, and moistens your mouth, eyes, nose, hair, skin, joints, and digestive tract. Limiting your water intake can result in dehydration, elevated body temperature, fatigue, decreased performance, and increased risk of heat-related illness. Consume at least ten 8-ounce glasses of water per day. Use the water calculator below to determine your suggested daily water intake based on your weight and activity level.