How many carbs are in watermelon?
Watermelon has 11.6 g of total carbs per 1 cup diced (152 g) — about 11 g net carbs after 0.6 g of fiber. That's 7.6 g of carbs per 100 g, roughly 4% of the 275 g Daily Value.
USDA FoodData Central · raw · FDC 167765
Carbs by portion
| Portion | Total carbs | Net carbs | Fiber | Sugar | Calories |
|---|---|---|---|---|---|
| 1 cup diced (152 g) | 11.6 g | 11 g | 0.6 g | 9.4 g | 46 |
| 100 g | 7.6 g | 7.2 g | 0.4 g | 6.2 g | 30 |
| 1 oz (28 g) | 2.2 g | 2.1 g | 0.1 g | 1.8 g | 9 |
Net carbs = total carbs − fiber (the carbs that raise blood sugar, used in keto/low-carb tracking). Values computed from USDA per-100 g data (FDC 167765, SR Legacy). raw.
Watermelon is the lightest of the sweet fruits on carbs: about 11.6 g of total carbs in a 1-cup serving of diced fruit (152 g), which is about 11 g net carbs after just 0.6 g of fiber. That’s only 7.6 g of carbs per 100 g, for roughly 46 calories a cup — less than half the carbs of a cup of grapes. The reason is simple: watermelon is about 92% water, so there isn’t much room left for carbohydrate in the first place.
Why net carbs barely move the number
Net carbs — total carbs minus fiber — is the figure that matters for keto, low-carb and blood-sugar tracking, because fiber is the carbohydrate your body doesn’t turn into glucose. Watermelon has almost no fiber (0.6 g per cup), so net carbs sit essentially at the total, around 11 g. As with the other sweet fruits, most of those carbs are sugar — about 9.4 g per cup, roughly 81% of the total. What sets watermelon apart isn’t a lower sugar share; it’s that the whole carbohydrate load is small to begin with, diluted by all that water.
How a cup fits a daily budget
In practical terms, watermelon is the one sweet fruit here that can fit a low-carb day. A full cup at about 11 g net carbs is still too much to eat freely on strict keto — but because it’s mostly water, a small portion behaves very differently: half a cup is only about 5.5 g net carbs, light enough to slot into a relaxed keto or low-carb plan where grapes or mango simply wouldn’t. The catch is that watermelon is easy to overeat — a big wedge can run past 20 g of carbs — so the portion, not the fruit, is what decides whether it fits.
If you want the other side of the macro picture, see protein in watermelon — and for any packaged watermelon juice or snack, always read the label’s own carb and sugar lines.
Frequently Asked Questions
How many carbs are in a cup of watermelon?
About 11.6 g of total carbohydrate in a 1-cup serving of diced fruit (152 g), which is 7.6 g per 100 g (USDA FDC 167765). That cup is only about 46 calories, because watermelon is roughly 92% water.
What are the net carbs in watermelon?
About 11 g net carbs per cup — total carbs (11.6 g) minus fiber (0.6 g). Watermelon has very little fiber, so net carbs sit right at the total — but the total itself is low, which is what makes watermelon the most forgiving of the sweet fruits.
How much of the carbs in watermelon is sugar?
Most of it. A cup has about 9.4 g of sugar out of 11.6 g of total carbs — roughly 81%. The difference from sweeter fruits isn't the sugar share, it's that there's simply far less carbohydrate per cup because it's mostly water.
Is watermelon keto or low-carb?
It's the closest of the sweet fruits to fitting. A full cup is about 11 g net carbs, which is too much for a strict keto budget if you eat a lot — but because watermelon is ~92% water, a small portion (half a cup, ~5.5 g net) can fit a low-carb or relaxed keto day where grapes or mango can't.
How many carbs are in a wedge of watermelon?
Roughly 21 g of carbs for a large wedge. A typical wedge (about 1/16 of a melon, ~280 g) carries around 21 g of total carbs (about 20 g net, ~17 g sugar). The carb count climbs with portion size because it's easy to eat a lot of watermelon.
When was this data last verified?
2026-06-04, against USDA FoodData Central FDC 167765 (Watermelon, raw; SR Legacy). We re-verify reference pages periodically.
Whole-food values are USDA reference data, not a Labelgrade (that score is for branded packaged products). See our methodology and the macro calculator to turn this into a daily target.