A half cup of fresh blueberries contains about 11 grams of total carbohydrates. A full cup, which is closer to what most people toss into a smoothie or bowl of oatmeal, has roughly 22 grams. That puts blueberries in the moderate range for fruit, lower than bananas and grapes but higher than strawberries and raspberries.
Carbs, Fiber, and Sugar Per Serving
Here’s the breakdown for common serving sizes of fresh blueberries:
- Half cup (74 g): 11 g total carbs, 2 g fiber, about 7 g sugar
- One cup (148 g): 22 g total carbs, 4 g fiber, about 15 g sugar
Most of those carbs come from natural sugars, primarily glucose and fructose in roughly equal amounts with a small amount of sucrose. The fiber content is modest but meaningful. It slows digestion, which helps prevent a sharp spike in blood sugar after eating.
Net Carbs for Low-Carb Diets
If you’re counting net carbs (total carbs minus fiber), a half cup of blueberries comes to about 9 grams. That’s a useful number for anyone on a keto or low-carb plan, where the daily target is often 25 to 50 grams of net carbs depending on how strict the approach is.
A half cup is a reasonable keto-friendly portion. It’s enough to add flavor and sweetness to yogurt or a handful to snack on without using up most of your daily carb budget. A full cup, at roughly 18 grams of net carbs, takes a bigger bite out of that allowance but can still fit into a moderately low-carb plan.
How Blueberries Affect Blood Sugar
Blueberries have a glycemic index of about 40, which falls in the low category (anything under 55 is considered low). That means they raise blood sugar gradually rather than causing a rapid spike. For comparison, white bread scores around 75 and watermelon hits about 72.
The combination of fiber, water content, and the specific sugar profile in blueberries contributes to this slower absorption. This makes them one of the more blood sugar-friendly fruits, which is partly why they show up so often on lists of recommended foods for people managing diabetes or insulin resistance.
How Blueberries Compare to Other Fruits
Per cup of raw fruit, here’s how blueberries stack up on total carbs:
- Raspberries: about 15 g (lowest common berry)
- Strawberries: about 12 g
- Blueberries: about 22 g
- Grapes: about 27 g
- Banana (one medium): about 27 g
Blueberries are noticeably higher in carbs than strawberries and raspberries. If you’re trying to minimize carbs while still eating fruit, those two berries give you a larger volume for fewer grams. But blueberries still come in well below tropical fruits like mangoes and pineapple, which can pack 25 or more grams in a single cup.
Fresh vs. Frozen vs. Dried
Fresh and frozen blueberries have virtually identical carb counts, since freezing doesn’t change the nutritional composition. Frozen berries are picked and processed at peak ripeness, so they’re nutritionally equivalent to fresh and often more affordable.
Dried blueberries are a different story. The water is removed, which concentrates the sugars dramatically. A quarter cup of dried blueberries can contain 30 or more grams of carbs, and many brands add sugar during processing. If carb count matters to you, always check the label on dried varieties. Blueberry juice and blueberry-flavored products also tend to be significantly higher in sugar, since they strip out the fiber that slows absorption in the whole fruit.