The chemical formula for carbohydrate is carbon, oxygen and hydrogen, the number of atoms varies on what carbohydrate. Carbohydrate general formula is CnH2nOn" e.g: Glucose - C6H12O6. Carbohydrates consist of the elements carbon, hydrogen and oxygen with a ratio of hydrogen twice that of carbon and oxygen. Carbohydrates include sugars, starches, cellulose and many other compounds found in living organisms.