How many carbs are in sugar?
One teaspoon of granulated sugar (4g) has about 4g of carbohydrate. Sugar is pure carbohydrate with no fiber, protein, or fat.
Carbs by portion
| Portion | Total carbs | Fiber | Net carbs |
|---|---|---|---|
| 1 teaspoon (4g) | 4.0g | 0.0g | 4.0g |
| 1 cup (188g) | 187.2g | 0.0g | 187.2g |
| 1 RACC (8g) | 8.0g | 0.0g | 8.0g |
| 100 grams | 99.6g | 0.0g | 99.6g |
Net carbs
One teaspoon of sugar has about 4g of net carbs. Sugar has zero fiber, so total carbs and net carbs are the same. One tablespoon has about 12g. See the net carbs guide.
Glycemic index of sugar
The glycemic index of sugar is about 65. Table sugar (sucrose) has a glycemic index of 65. Sucrose is a disaccharide of glucose (GI 100) and fructose (GI 23), so its blended GI falls in the mid-range. This is lower than many people expect for 'pure sugar.'
For diabetes
One teaspoon of sugar adds 4g of pure carbs. The impact on blood sugar depends on total meal context: a teaspoon in a cup of coffee alongside a protein-rich breakfast barely registers. Added sugar in processed foods is harder to track because it accumulates across many servings. In the US, the American Heart Association recommends under 25g of added sugar per day for women and 36g for men, regardless of diabetes status. See the diabetes carb-counting guide.
Keto and low carb
Sugar has no place in keto. One tablespoon (12g) uses more than half a typical keto daily carb budget. Erythritol, allulose, and stevia are common keto-compatible sweeteners with zero or minimal glucose impact.
Good to know
Table sugar is sucrose: one molecule of glucose bonded to one molecule of fructose. The glycemic index of 65 reflects how the blended sugar behaves. Brown sugar and white sugar have nearly identical carb counts (brown sugar retains a small amount of molasses, which adds a trace of minerals but negligible nutrition). Powdered sugar is the same as granulated sugar but ground fine. Turbinado and raw sugar are also essentially the same in carbs.
Full nutrition (per 100g)
- Calories: 385.0 kcal
- Carbohydrate: 99.6g
- Fiber: 0g
- Sugars: n/ag
- Protein: 0.0g
- Fat: 0.32g
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Get the appFrequently asked questions
How many carbs are in sugar?
One teaspoon (4g) of granulated sugar has about 4g of carbs. One tablespoon has 12g.
Is sugar pure carbohydrate?
Yes. Sugar is 99.6g of carbohydrate per 100g, with the remaining 0.4g as trace fat. There is no protein, fiber, or meaningful nutrients.
What is the glycemic index of sugar?
Table sugar (sucrose) has a GI of about 65, which is moderate, not as high as pure glucose (100) because half of sucrose is fructose, which has a lower GI.
Does brown sugar have fewer carbs than white sugar?
No. Brown sugar and white sugar have essentially identical carb counts. Brown sugar is white sugar with a small amount of molasses added back.
How many carbs are in a cup of sugar?
One cup (188g) of granulated sugar has about 187g of carbohydrate.