Chicken Breast Calories & Protein: Complete Nutrition Breakdown

Chicken breast is the most popular lean protein source worldwide. A 100g serving of raw, skinless, boneless chicken breast contains 120 calories and 22.5g of protein (USDA FDC #171077). When cooked (grilled), the same portion concentrates to approximately 165 calories and 31g protein per 100g due to 25% moisture loss during cooking.

The difference between raw and cooked nutrition values confuses many people. When chicken cooks, it loses water (approximately 25% of its weight). This means the nutrients in 100g of raw chicken become concentrated into approximately 75g of cooked chicken. Per 100g of cooked weight, the values appear higher because you are looking at a more concentrated food. Always specify whether you are measuring raw or cooked weight when tracking nutrition.

Here are calories for common chicken breast serving sizes (grilled, skinless): One medium breast (~170g cooked) = 281 calories, 53g protein. Half breast (~85g cooked) = 140 calories, 26g protein. 4 oz / 113g cooked = 186 calories, 35g protein. 6 oz / 170g cooked = 281 calories, 53g protein. 8 oz / 227g cooked = 375 calories, 70g protein.

Adding skin increases calories significantly. Skinless grilled breast: 165 cal, 3.6g fat per 100g. Skin-on grilled breast: approximately 219 cal, 12.6g fat per 100g. Removing skin saves roughly 55 calories and 9g of fat per 100g. For calorie-controlled diets, always choose skinless.

Chicken breast is one of the best foods for weight loss because it has an extremely high protein-to-calorie ratio. With 31g protein and only 165 calories per 100g cooked, approximately 75% of its calories come from protein. This high thermic effect of protein (TEF) means your body burns more calories digesting it compared to carbs or fat. A typical 150g serving provides over 46g of protein — nearly the entire daily requirement for many people — at only 248 calories.