How many carbs are in grapefruit?
Grapefruit has 13.2 g of total carbs per 1/2 medium (123 g) — about 11.2 g net carbs after 2 g of fiber. That's 10.7 g of carbs per 100 g, roughly 5% of the 275 g Daily Value.
USDA FoodData Central · raw · FDC 174673
Carbs by portion
| Portion | Total carbs | Net carbs | Fiber | Sugar | Calories |
|---|---|---|---|---|---|
| 1/2 medium (123 g) | 13.2 g | 11.2 g | 2 g | 8.5 g | 52 |
| 100 g | 10.7 g | 9.1 g | 1.6 g | 6.9 g | 42 |
| 1 oz (28 g) | 3 g | 2.5 g | 0.5 g | 2 g | 12 |
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 174673, SR Legacy). raw.
Grapefruit has earned its “diet fruit” reputation honestly. A standard serving — half a medium grapefruit (123 g) — carries about 13 g of total carbohydrate, which is 10.7 g per 100 g. Subtract the 2 g of fiber and you’re left with roughly 11 g of net carbs. For a fruit, that’s genuinely low, and it’s why grapefruit shows up on so many low-carb and calorie-conscious plans.
Why grapefruit is a lower-carb citrus
Net carbs are total carbs minus fiber, and grapefruit benefits on both ends: a modest carbohydrate total and a fair bit of fiber for the portion. Of the ~13 g of carbs in half a fruit, about 8.5 g is sugar and 2 g is fiber, leaving the ~11 g net figure. Per 100 g that’s 10.7 g carbs, 1.6 g fiber, 6.9 g sugar, for only about 52 calories a half. Among everyday citrus, grapefruit’s sugar load is on the lighter side, which keeps its numbers down — and the water-heavy, low-calorie profile is exactly why a half-grapefruit feels filling without much carbohydrate cost.
What this means for keto and low-carb
For low-carb eating, grapefruit is a solid yes: ~11 g net carbs per half leaves plenty of room on a moderate plan, and you get a refreshing, vitamin-C-rich fruit for the carbs. On strict keto it’s borderline-workable — half a fruit is about half of a 20 g daily budget, so it’s a “fits in small amounts” food rather than a free one. Either way, grapefruit is one of the more carb-efficient fruits you can pick. One practical note: grapefruit can interact with several common medications, so check with a pharmacist if you take prescription drugs — that’s unrelated to carbs but worth flagging.
Grapefruit’s value runs well beyond its low carb count — vitamin C, potassium, and lycopene in the pink varieties. For the rest of the nutrition picture, see protein in grapefruit. And for any sweetened or canned grapefruit, check the label’s carb and fiber lines, since added sugar changes the math fast.
Frequently Asked Questions
How many carbs are in half a grapefruit?
About 13 g of total carbohydrate in half a medium grapefruit (123 g), which is 10.7 g per 100 g (USDA FDC 174673). With about 2 g of fiber in that half, the net carbs come out to roughly 11 g — making grapefruit one of the more low-carb-friendly fruits.
What are the net carbs in grapefruit?
Roughly 11 g net carbs per half — total carbs (~13 g) minus the ~2 g of fiber. Grapefruit's net number is genuinely on the low side for fruit, which is a big part of why it has a long-standing reputation as a 'diet' food.
How much of grapefruit's carbs are sugar versus fiber?
Mostly sugar, but less than sweeter fruits. Half a grapefruit has about 8.5 g of sugar and 2 g of fiber out of its ~13 g total carbs. The sugar load is modest for a fruit, which keeps both total and net carbs comparatively low.
Is grapefruit keto or low-carb?
It's low-carb-friendly but not strictly keto. At ~11 g net carbs per half, grapefruit fits a moderate low-carb plan comfortably and even works in small amounts on keto, though half a fruit is a noticeable chunk of a strict 20 g day. As citrus goes, it's one of the better-fitting choices.
How many carbs are in a whole grapefruit?
A whole medium grapefruit is about 246 g, so roughly 26 g of total carbs and around 22 g net carbs (after ~3.9 g fiber). Most people eat half, which keeps the serving near 11 g net — a sensible portion if you're watching carbs.
When was this data last verified?
2026-06-04, against USDA FoodData Central FDC 174673 (Grapefruit, raw, pink and red, all areas; SR Legacy). We re-verify reference pages periodically and update when USDA revises the entry.
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.