How many carbs are in watermelon?
A cup of diced watermelon (152g) has about 11.5g of carbohydrate and 11g of net carbs. Portion size moves the number quickly because a single wedge can be nearly three cups.
Carbs by portion
| Portion | Total carbs | Fiber | Net carbs |
|---|---|---|---|
| 1 cup diced (152g) | 11.5g | 0.6g | 10.9g |
| 1 watermelon balls (122g) | 9.2g | 0.5g | 8.7g |
| 1 cup, balls (154g) | 11.6g | 0.6g | 11.0g |
| 1 wedge (286g) | 21.6g | 1.1g | 20.4g |
| 100 grams | 7.5g | 0.4g | 7.2g |
Net carbs
A cup of diced watermelon has about 11g of net carbs, which is total carbs (11.5g) minus fiber (0.6g). Watermelon is low in fiber, so net carbs track closely with total carbs here. A full wedge (286g) brings that to roughly 20g net. See the net carbs guide for when net vs total carbs matters.
Glycemic index of watermelon
The glycemic index of watermelon is about 72. A high glycemic index means watermelon raises blood sugar faster than most fruits, but its low carb density per serving keeps the overall glycemic load moderate. A cup of diced watermelon has a glycemic load of around 4, which is low.
For diabetes
Watermelon has a high glycemic index (72) but a low glycemic load per cup because it is mostly water. One cup (152g) has about 11.5g of total carbs, which is a manageable portion for most meal plans. The problem is portion creep: a restaurant-size wedge can weigh 280g or more and push carbs past 20g in one serving. Count by total carbs, measure before eating, and pair with protein to slow the rise. See the diabetes carb-counting guide for a practical approach.
Keto and low carb
One cup of diced watermelon has about 11g of net carbs, which is more than a third of a strict 20g daily keto budget. A full wedge hits 20g net on its own. Watermelon does not fit standard keto. A small controlled portion of two or three cubes can be worked in if carbs are tracked precisely, but it is easy to overshoot.
Good to know
Watermelon is about 92% water by weight, which is why it looks like a low-carb fruit at first glance. The carb density per 100g is genuinely low (7.55g), but people rarely eat 100g. A standard restaurant wedge weighs 280 to 300g and delivers 21g of carbs, nearly all of it sugar. Seedless varieties and yellow-flesh watermelon have essentially the same carb content as the standard red variety. Watermelon juice concentrates the sugar and removes the small amount of fiber, so a glass of watermelon juice hits harder than eating the flesh.
Full nutrition (per 100g)
- Calories: 30.0 kcal
- Carbohydrate: 7.55g
- Fiber: 0.4g
- Sugars: 6.2g
- Protein: 0.61g
- Fat: 0.15g
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Get the appFrequently asked questions
How many carbs are in watermelon?
A cup of diced watermelon (152g) has about 11.5g of carbs. A full wedge (about 1/16 of a melon, 286g) has about 21.6g of carbs.
How many net carbs are in watermelon?
Watermelon has very little fiber, so net carbs are close to total carbs. One cup (152g) has about 11g of net carbs. A wedge (286g) has about 20g of net carbs.
Is watermelon high in sugar?
Watermelon is about 82% of its carbs as sugar. One cup has roughly 9.4g of sugar. Most of that sugar is fructose and glucose, which absorb quickly given the fruit's high GI of 72.
Can diabetics eat watermelon?
Yes, in a measured portion. One cup (152g) has about 11.5g of total carbs, which fits a standard 15g carb exchange. The high GI means blood sugar rises faster than with lower-GI fruits, so keeping portions to one cup and pairing with protein helps.
Is watermelon keto-friendly?
Not for most keto plans. One cup has about 11g of net carbs, and it is easy to eat two or three cups at a sitting. A few cubes as a garnish can work if the rest of the day is very low in carbs.
What is the glycemic index of watermelon?
Watermelon's GI is 72, which is high. However, its glycemic load per cup is around 4 (low), because a cup contains relatively few total carbs. Larger portions push the glycemic load higher.