Calories in Watermelon

How Many Calories Are in Watermelon?

Watermelon is one of the lightest fruits you can eat. One cup of diced watermelon contains about 46 calories, and by weight it comes in at roughly 30 calories per 100 grams — among the lowest of any common fruit. The reason is simple: watermelon is about 92% water, so each bite is mostly hydration with a small amount of natural sugar.

Almost all of watermelon’s calories come from carbohydrates, with no fat and only a trace of protein. That makes it a refreshing, guilt-free summer snack that fills you up for very few calories.

Watermelon Calories by Serving

Serving	Amount	Calories	Carbs (g)	Sugar (g)
Small cube	~10 g	~3	0.8	0.6
Half cup diced	~76 g	~23	6	5
One cup diced	~152 g	~46	12	9
Wedge (1/16 melon)	~286 g	~86	22	18
100 grams	100 g	~30	8	6

These figures are for fresh watermelon flesh. Watermelon juice is slightly more concentrated, and dried watermelon or watermelon candy can be dramatically higher in calories per gram because the water is gone.

Is Watermelon High in Sugar?

Watermelon tastes intensely sweet, which leads many people to assume it is loaded with sugar. In reality it holds only about 6 grams of sugar per 100 grams — less than grapes, mangoes or bananas. Its high glycemic index means the sugar it does contain is absorbed quickly, but because the total amount per serving is small and diluted by so much water, the actual sugar load (the glycemic load) of a normal portion is low. For most people, a cup or two of watermelon is a light, low-sugar choice.

Macros and Nutrition in Watermelon

A cup of watermelon provides about 12 grams of carbohydrate, 9 grams of natural sugar and under 1 gram of fiber, with negligible fat and protein. Watermelon is a notable source of vitamin C and vitamin A, and it is one of the richest dietary sources of lycopene — the same red antioxidant found in tomatoes. It also contains citrulline, an amino acid that the body converts to arginine, which is involved in blood-vessel function. Its standout feature, though, is hydration: a few cups deliver a meaningful amount of water on a hot day.

Does Watermelon Fit a Healthy Diet?

Watermelon is a near-ideal fruit for weight management and hydration. Its rock-bottom calorie density means you can eat a satisfying volume for very little energy, and its water and lycopene content add genuine nutritional value. The main caveat is portion creep — because it is so light and pleasant, it is easy to eat several cups, which adds up the natural sugar even if the calories stay reasonable. Pairing watermelon with a protein like feta cheese or a handful of nuts makes for a more balanced, sustaining snack.