How many calories are in 1 slice of white cake with buttercream icing?

October 23, 2025 •

4 min read

A slice of white cake with buttercream icing can contain anywhere from 250 to over 450 calories, with the average falling around 350-400 calories. This wide range depends significantly on the cake's size, frosting thickness, and ingredients, whether it is homemade or store-bought. Understanding this calorie count helps individuals make informed dietary choices.

Quick Summary

The calorie count for a slice of white cake with buttercream icing varies widely based on portion size, frosting quantity, and specific ingredients. Average estimates suggest a range of 350-400 calories per slice for many commercial and homemade versions. The highest concentration of calories typically comes from the sugar and fat in the rich buttercream frosting.

Key Points

Average Calorie Range: A standard slice of white cake with buttercream icing typically contains 350-400 calories, but this can vary widely.
Impact of Portion Size: The physical size of the slice dramatically affects the total calories, with smaller servings having significantly less.
Buttercream is a Calorie Contributor: The rich, sugary buttercream frosting is often the most calorie-dense component of the dessert.
Homemade vs. Store-Bought: Ingredients and preparation differ between homemade and store-bought cakes, leading to different calorie counts.
Healthier Alternatives Exist: Opting for modifications like reduced sugar, fruit toppings, or Greek yogurt frosting can lower the overall calorie intake.
Check Labels for Accuracy: For store-bought cakes, the most accurate calorie information is on the manufacturer's nutrition label.

Factors Influencing Calorie Count

The number of calories in a slice of white cake with buttercream icing is not a fixed figure. Several variables contribute to the final energy value, which is why calorie estimates can differ significantly.

Slice Size and Weight

One of the most obvious factors is the size of the slice itself. A small, thin slice from a large-diameter cake will naturally have fewer calories than a thick, generous wedge. For example, nutrition data shows a small piece can be as low as 251 calories, while larger servings can be much higher. A standardized measurement, such as per 100 grams, can provide a more consistent reference, though most people do not weigh their cake at home.

Ingredients and Recipe Variations

The recipe for both the cake and the icing plays a critical role. A rich, dense white cake made with full-fat butter and whole milk will have a higher calorie density than a lighter sponge cake made with a reduced-fat recipe. Similarly, the buttercream icing can vary. A traditional American buttercream, which is often a mix of butter, powdered sugar, and milk, is very high in sugar and fat. A meringue-based buttercream, like Swiss or Italian, can sometimes be slightly less dense but still packs a caloric punch. Add-ins like fillings, sprinkles, or extra sugar decorations also increase the overall calorie load.

Homemade vs. Store-Bought

Homemade and store-bought cakes have different calorie profiles. Store-bought cakes often use specific commercial recipes designed for a particular texture and shelf life, which may include hydrogenated oils or high-fructose corn syrup. This can result in a calorie count that differs from a homemade cake made with standard pantry ingredients. When buying a cake, checking the nutritional label provided by the manufacturer is the most accurate way to determine its value. The calorie count for a slice of cake from a grocery store bakery can be around 360 calories, but this can vary by brand.

Calorie Breakdown and Comparison

To understand where the calories come from, it's helpful to look at the macronutrient breakdown. The majority of the calories in a white cake with buttercream come from carbohydrates (sugar and flour) and fat (butter or oil).

Macronutrient Profile of a Typical Slice

A standard slice of white cake with buttercream is primarily composed of fat and sugar. A sample nutrition fact table for a store-bought cake reveals the high percentage of daily value from saturated fat and sugar. The protein content is generally minimal, providing little in the way of satiety. The cake provides energy but offers very little in terms of essential vitamins, minerals, or fiber.

Comparison Table: Cake vs. Healthier Desserts


Dessert Item	Serving Size	Approximate Calories	Key Macronutrients
White Cake with Buttercream Icing	1 slice (approx. 80-90g)	350-400	High in carbs (sugar) and fat
Greek Yogurt with Berries	1 cup yogurt + 1/2 cup berries	150-200	High in protein, low fat, and fiber
Apple Crumble	1 serving (approx. 150g)	280-320	Carbs, some fiber, moderate fat
Dark Chocolate (70%+)	1 oz (28g)	160-170	High in fat, moderate sugar, rich in antioxidants
Lightly Sweetened Whipped Cream	1/2 cup	100-150	Moderate fat, low sugar

Healthier Alternatives and Modifications

For those who want to enjoy the flavor of cake without the high calorie count, several modifications can be made.

Modify Your Recipe

Reduce Sugar: Recipes can often be made with 25-30% less sugar without a significant change in taste.
Substitute Fats: Use unsweetened applesauce, mashed banana, or Greek yogurt to replace some of the oil or butter.
Alternative Flours: Incorporate whole wheat or almond flour for more fiber and nutrients, but this may affect the cake's texture.
Portion Control: Simply serve smaller slices to reduce calorie intake. This is the easiest and most direct method.

Alternative Frostings

Beyond modifying the cake, altering the icing is another powerful way to cut calories. Buttercream is very rich, so switching to a lighter alternative can make a big difference.

Greek Yogurt Frosting: Mix Greek yogurt with a bit of maple syrup and vanilla extract for a healthier, protein-rich topping.
Lightened Cream Cheese Frosting: Use light cream cheese and reduce the amount of powdered sugar.
Fresh Fruit Topping: Use fresh berries or a fruit compote to add natural sweetness without the heavy fat and sugar of traditional icing.
Whipped Cream: A dollop of lightly sweetened whipped cream is much lighter than a thick layer of buttercream and still provides a creamy texture.

The Bottom Line

Understanding how many calories are in 1 slice of white cake with buttercream icing involves considering several factors, including portion size, ingredients, and whether it's homemade or store-bought. While a typical slice can contain anywhere from 350 to 400 calories or more, there are many ways to enjoy a lighter version of this classic dessert. By adjusting recipes, opting for healthier frosting alternatives, or simply practicing mindful portion control, you can still satisfy your sweet tooth without overindulging. Making small changes can lead to a significant difference in the final nutritional profile. For those who want more precise figures, examining manufacturer nutrition labels or using a reliable food calorie database is recommended.

Conclusion

Determining the exact number of calories in a slice of white cake with buttercream icing is complex due to variations in size and recipe. The average can range significantly, but a reasonable estimate is often between 350 and 400 calories per typical slice. The high content of sugar and fat, primarily from the buttercream, contributes heavily to this count. By being mindful of portion sizes and exploring healthier substitutions like fruit toppings or Greek yogurt frosting, you can manage your intake without completely sacrificing dessert. Making informed choices about ingredients and preparation methods is key to enjoying this treat in a more balanced way.

Frequently Asked Questions

To reduce calories, you can decrease the amount of sugar by up to 30%, substitute some of the fat with unsweetened applesauce or Greek yogurt, and use egg whites instead of whole eggs.

Not necessarily. Store-bought cakes often contain commercial ingredients and can have a higher calorie count than a mindfully prepared homemade version. The nutritional information on store-bought packaging, however, provides a precise number.

For a lighter topping, consider a frosting made with Greek yogurt, a dollop of lightly sweetened whipped cream, or a fresh fruit compote. These alternatives significantly cut down on the sugar and fat found in traditional buttercream.

Yes, portion size is one of the most important factors. A large, thick slice can have double the calories of a smaller, more modest serving, even from the same cake.

Buttercream icing is high in calories because its main ingredients are butter and powdered sugar. Both are dense in calories and contribute to the high-fat and high-sugar content of the frosting.

You can use alternative flours like whole wheat or almond flour to increase fiber content and nutrients. However, this may alter the cake's texture, so it's best to experiment with small substitutions first.

Compared to some alternatives, white cake with buttercream is quite high in calories. For example, a bowl of Greek yogurt with berries or a serving of dark chocolate is typically much lower in calories while providing more nutrients.