How may caliries do you need in a day?

For good health, you need to eat the same number of calories that your body burns. This depends upon your sex, your age, your weight, your height and your level of activity. I suggest you consult a reputable dietary science website such as the Mayo Clinic site listed below. A rough estimate for a female young adult would be 1600-1800 calories per day, and 2000-2200 calories per day for a young adult male.