The main differences between cooked and uncooked (raw) rice come down to water content, texture, digestibility, weight/volume, and nutritional density per gram.
Water content and texture: Uncooked rice is hard, dry, and contains very little moisture (roughly 10-12%). When rice is cooked, it absorbs water through boiling or steaming, causing the starch granules to swell and gelatinize. This process, called gelatinization, softens the grain and gives cooked rice its familiar tender, fluffy or sticky texture depending on the rice variety. Cooked rice typically contains 65-70% water by weight.
Weight and volume: Because cooked rice absorbs water, it roughly doubles or triples in weight and volume compared to its uncooked state. For example, one cup of uncooked rice generally yields about 2.5 to 3 cups of cooked rice. This is important for recipe measurements and portion planning.
Digestibility: Raw rice is very difficult for the human digestive system to break down and is not safe to eat in that state — it can cause digestive upset and, importantly, uncooked or improperly stored rice can harbor Bacillus cereus spores, a bacterium that can cause food poisoning if the rice isn't cooked and handled properly. Cooking rice breaks down resistant starches, making it digestible and safe to consume.
Nutrition per gram: Because cooked rice contains added water, its nutrient and calorie density per gram is lower than uncooked rice. For instance, 100 grams of uncooked white rice has significantly more calories, carbohydrates, and other nutrients than 100 grams of cooked rice, simply because the cooked version is diluted with water. This is why nutrition labels often specify whether values are for cooked or uncooked/dry rice.
Storage: Uncooked rice, kept dry and sealed, can last for years, while cooked rice spoils quickly and should be refrigerated and eaten within a few days due to bacterial growth risk.