How many calories in green beans? A cup of 120g of green beans has 20 calories. It has 17% sodium, 1% carbohydrates, 4% dietary fiber, Vitamin K 9%, vitamin A, 4% vitamin C, 2% calcium and 4% iron. It is one of the food items with low calories and still has plenty of nutrition value. It is rich in Vitamin K, which aids in prevention of menstrual bleeding, gastrointestinal bleeding, anemia, gum bleeding, eye hemorrhages, clotting time, osteoporosis etc. Green beans are rich in Vitamin A, which controls the beta-carotene, rich in Vitamin C, which prevents cholesterol, heart attack, arterie blocks and strokes.