Calories in Watermelons: Nutrition Facts & Serving Sizes
Per 1 cup, diced (152g)
Per 100g
Source: USDA FoodData Central, SR Legacy, March 2026.
One cup of diced watermelon (152g) contains 46 calories with 0.9g of protein, 11.6g of carbs, and 0.3g of fat. Per 100g, watermelon provides just 30 calories, 0.6g of protein, 7.6g of carbs, and 0.2g of fat. Watermelon is one of the most hydrating foods available at roughly 92% water by weight. The low calorie density makes it one of the best volume-eating fruits for anyone on a cut. Most of the carbs come from natural sugars (6.2g per 100g), but because watermelon is mostly water, the sugar impact per serving is minimal. The standout micronutrient is vitamin A at 28mcg per 100g. Watermelon is also one of the richest dietary sources of lycopene, a red carotenoid with strong antioxidant properties. For anyone who wants a high-volume, sweet snack for under 100 calories, a large 2-cup serving of watermelon delivers that at just 91 calories.
Nutrition Highlights
Calories by Serving Size
| Serving | Cal | Protein | Carbs | Fat | Fiber |
|---|---|---|---|---|---|
| 1 serving (280g) | 84 | 1.7g | 21.3g | 0.6g | 1.1g |
| 1 cup, diced (152g) | 45.6 | 0.9g | 11.6g | 0.3g | 0.6g |
| 10 watermelon balls (122g) | 36.6 | 0.7g | 9.3g | 0.2g | 0.5g |
| 1 cup, balls (154g) | 46.2 | 0.9g | 11.7g | 0.3g | 0.6g |
| 1 wedge (approx 1/16 of melon) (286g) | 85.8 | 1.7g | 21.7g | 0.6g | 1.1g |
| 1 melon (15" long x 7-1/2" dia) (4518g) | 1355.4 | 27.1g | 343.4g | 9g | 18.1g |
| 100g | 30 | 0.6g | 7.6g | 0.2g | 0.4g |
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Full Nutrition Facts (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 30 | 2% |
| Protein | 0.6g | 1% |
| Total Fat | 0.2g | |
| Total Carbohydrates | 7.6g | 3% |
| Dietary Fiber | 0.4g | 1% |
| Sugars | 6.2g | 12% |
| Sodium | 1mg |
Vitamins & Minerals (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calcium | 7mg | 1% |
| Iron | 0.2mg | 1% |
| Potassium | 112mg | 2% |
| Vitamin A | 28mcg | 3% |
| Vitamin C | 8.1mg | 9% |
| Magnesium | 10mg | 2% |
| Phosphorus | 11mg | 1% |
| Zinc | 0.1mg | 1% |
| Selenium | 0.4mcg | 1% |
| Folate | 3mcg | 1% |
| Niacin (B3) | 0.2mg | 1% |
% Daily Values based on a 2,000 calorie diet (FDA reference).
Health Benefits of Watermelons
Watermelon is one of the richest dietary sources of lycopene, the red pigment that gives it its color. Lycopene is a carotenoid antioxidant studied extensively for its ability to neutralize free radicals. Research links higher lycopene intake to reduced oxidative stress and inflammation, both of which accumulate with intense training.
The high water content of watermelon (around 92%) makes it one of the most hydrating foods available. Eating water-rich foods contributes to total fluid intake and can help maintain hydration levels during hot weather or after heavy sweat sessions. Adequate hydration directly impacts strength, endurance, and cognitive performance during training.
Watermelon contains a small amount of L-citrulline, an amino acid that converts to L-arginine in the body and supports nitric oxide production. Nitric oxide dilates blood vessels, which can improve blood flow to working muscles. While the amounts in a typical serving are modest compared to supplement doses, regular consumption may provide a cumulative effect.
At 30 calories per 100g, watermelon is an outstanding volume food for weight loss. A full wedge (286g, about one-sixteenth of a melon) contains only 86 calories and is filling due to its water and fiber content. The natural sweetness satisfies sugar cravings without triggering the calorie overload of processed sweets.
Vitamin C at 8.1mg per 100g contributes to immune support and collagen synthesis. Potassium at 112mg per 100g supports electrolyte balance, though it is lower than other fruits like banana or melon.
Dietary Considerations
Watermelon is naturally gluten-free, vegan, dairy-free, and paleo-friendly. It is not keto-friendly due to its sugar content (6.2g per 100g), though small portions can technically fit. For weight loss, watermelon is one of the best fruit choices due to its extremely low calorie density. Eating 2 cups (304g) for under 92 calories is genuinely filling thanks to the volume and water content. The glycemic index of watermelon is relatively high (around 72), but the glycemic load per typical serving is low because of the high water content. This means blood sugar impact is moderate in practice.
Daily Intake (100g)
100g of watermelon provides 2% of a 2,000-calorie diet.
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Frequently Asked Questions
How many calories in watermelon?
One cup of diced watermelon (152g) has 46 calories. Per 100g, watermelon contains 30 calories. A standard wedge (286g, one-sixteenth of a melon) has about 86 calories. Watermelon is one of the lowest-calorie fruits you can eat due to its high water content.
Is watermelon good for weight loss?
Yes, watermelon is great for weight loss. At 30 calories per 100g, you can eat a large portion for very few calories. The high water content makes it filling. A 2-cup serving satisfies sweet cravings for under 92 calories, making it a much better choice than candy, cookies, or other sweet snacks.
How much protein in watermelon?
Watermelon has only 0.6g of protein per 100g. One cup (152g) contains 0.9g. Watermelon is not a protein source at all. It is a carb and water fruit, so always pair it with a protein-rich food like cottage cheese, Greek yogurt, or a protein shake if you need to hit protein targets.
Is watermelon high in sugar?
Watermelon has 6.2g of sugar per 100g, which is moderate compared to other fruits. However, because watermelon is mostly water, the total sugar per serving is low. One cup (152g) contains 9.4g of sugar. This is all natural fruit sugar, not added sugar, and the glycemic load per serving is low.
Does watermelon have lycopene?
Yes. Watermelon is one of the richest dietary sources of lycopene, a red carotenoid with antioxidant properties. Lycopene is linked to reduced oxidative stress and inflammation. Watermelon actually contains more lycopene per gram than raw tomatoes, making it a top source of this compound.
Is watermelon keto-friendly?
Watermelon is not ideal for keto. At 7.6g of carbs per 100g with 0.4g of fiber, it has about 7.2g of net carbs per 100g. A 1-cup serving (152g) has about 11g of net carbs, which can use up most of a strict keto daily carb allowance. Stick to very small portions or avoid it on strict keto.
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