A standard two-tablespoon serving of peanut butter contains about 8 grams of total carbohydrates. Of those, 2 grams come from fiber and 3 grams from sugars, leaving only a few grams of net carbs. That makes peanut butter one of the lower-carb options among popular spreads and snack foods.
Carb Breakdown Per Serving
For a 32-gram (two-tablespoon) serving of smooth peanut butter, the USDA lists the following carbohydrate profile:
- Total carbohydrates: 8 g
- Dietary fiber: 2 g
- Sugars: 3 g
If you’re tracking net carbs (total carbs minus fiber), that’s roughly 6 grams per serving. The remaining carbohydrates that aren’t classified as fiber or sugar are mostly starches naturally present in peanuts.
Peanut butter is primarily a fat and protein source. Most of its calories come from healthy fats, with protein making up the next largest share. Carbohydrates contribute a relatively small portion of its total energy, which is why it fits comfortably into low-carb and keto eating patterns in moderate amounts.
How Peanut Butter Affects Blood Sugar
Peanuts have a glycemic index of just 14, placing them among the lowest-GI foods available. For context, anything under 55 is considered low glycemic. This means peanut butter causes a very slow, minimal rise in blood sugar compared to foods like bread, crackers, or fruit spreads. The combination of fat, protein, and fiber in peanut butter slows digestion and helps blunt the blood sugar response, even when you eat it alongside higher-carb foods like toast or a banana.
Natural vs. Commercial Brands
The carb count can shift depending on whether you buy natural or commercial peanut butter. Natural varieties, made with just peanuts (and sometimes salt), contain zero added sugar. Brands like Smucker’s Natural, Crazy Richard’s, and Trader Joe’s Creamy Salted all list 0 grams of added sugar per serving. Their total carbohydrate count stays right around 6 to 8 grams.
Commercial brands like Jif and Skippy often include added sugar (sometimes listed as cane sugar or molasses) along with hydrogenated oils. This can bump the total carbs up by a gram or two per serving. The difference isn’t dramatic, but it adds up if you eat peanut butter daily or use more than the standard two-tablespoon portion. Checking the ingredient list is the simplest way to tell: if sugar appears as one of the first three ingredients, you’re getting a sweetened version.
Powdered Peanut Butter Comparison
Powdered peanut butter, like PB2, has a different nutritional profile because most of the fat has been pressed out. A two-tablespoon serving (13 grams of powder) contains about 5 grams of carbohydrates and 1 gram of fiber. That’s fewer total carbs than regular peanut butter, but the serving size is also less than half the weight. Gram for gram, powdered peanut butter actually has a higher carb concentration since removing the fat shifts the ratio toward protein and carbohydrates.
If your main goal is reducing carbs, regular peanut butter and powdered versions are fairly close per serving. Powdered peanut butter is more useful for cutting calories and fat than for significantly lowering carb intake.
Keeping Portions Accurate
Two tablespoons looks smaller than most people expect. When you scoop peanut butter with a knife or spoon straight from the jar, it’s easy to end up with three or four tablespoons without realizing it. That doubles your carb count to 12 to 16 grams, which still isn’t high, but matters if you’re carefully tracking macros for a keto or diabetic meal plan.
Using a food scale is the most reliable approach. Weigh out 32 grams and you’ll know exactly what you’re getting. If that feels excessive, even just leveling off your tablespoon instead of heaping it makes a noticeable difference in accuracy. Many people who feel peanut butter stalls their progress on a low-carb diet are simply eating more of it than they think.