How many carbs are in a slice of cake?
One slice of chocolate layer cake from a bakery (138g, roughly 1/12 of a whole cake) has about 73g of carbohydrate and 70g of net carbs. That is a significant carb load from a single dessert.
Carbs by portion
| Portion | Total carbs | Fiber | Net carbs |
|---|---|---|---|
| 1 slice (1/12 of a cake, 138g) | 72.9g | 3.0g | 69.9g |
| 1 piece (64g) | 33.8g | 1.4g | 32.4g |
| 1 oz (28g) | 15.0g | 0.6g | 14.4g |
| 100 grams | 52.8g | 2.2g | 50.6g |
Net carbs
One slice of chocolate layer cake has about 70g of net carbs, which is total carbs (73g) minus fiber (3g). The frosting alone accounts for a substantial share of the sugar. See the net carbs guide for when tracking net carbs helps.
Glycemic index of a slice of cake
The glycemic index of a slice of cake is about 38. Despite the high sugar content, chocolate cake has a moderate-to-low glycemic index because the fat from the frosting and the eggs slows digestion. The actual blood sugar load from a full slice is still large due to the sheer carb quantity.
For diabetes
A standard bakery slice has about 73g of carbs. That is a large dose. The fat in the cake slows the glucose rise somewhat, but the total carb load is high enough that most insulin users will need a meaningful correction. A smaller slice or a cupcake with minimal frosting can cut that in half. Count the frosting separately if you can estimate it: a thick layer adds 15 to 25g of carbs on its own. See the diabetes carb-counting guide.
Keto and low carb
One slice of chocolate cake has about 70g of net carbs, which is two to three times a typical day's entire keto budget. Cake does not fit a keto diet in standard form. Keto-adapted recipes using almond or coconut flour can reduce net carbs to 5 to 10g per slice.
Good to know
The USDA data here is for a commercially prepared chocolate cake with chocolate frosting from an in-store bakery. A homemade layer cake or a restaurant slice can vary widely. A thinner slice cut at 1/16 of the same cake comes out to about 55g with roughly 55g of carbs. Angel food cake runs lower at around 30g of carbs per slice because it has no fat and uses less sugar. Cheesecake, despite its rich texture, has only 25 to 35g of carbs per slice.
Full nutrition (per 100g)
- Calories: 389.0 kcal
- Carbohydrate: 52.84g
- Fiber: 2.2g
- Sugars: 39.96g
- Protein: 3.48g
- Fat: 20.05g
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Get the appFrequently asked questions
How many carbs are in a slice of cake?
A standard bakery slice of chocolate layer cake (138g) has about 73g of carbs. A thinner slice at 64g has about 34g of carbs.
How many carbs are in a cupcake?
A standard frosted cupcake (about 90g) has roughly 45 to 50g of carbs, depending on the frosting amount.
Is cake keto?
Standard cake is not keto. A slice has 70g or more of net carbs. Keto-adapted recipes using almond flour can bring that down to under 10g per slice.
How many carbs are in angel food cake?
Angel food cake is lower in carbs than most layer cakes. A standard slice (about 50g) has roughly 30g of carbs and almost no fat.
How does frosting affect the carb count of cake?
Frosting adds a significant share of the carbs. A thick layer of buttercream or chocolate frosting on one slice adds 15 to 25g of carbs on top of the cake itself.