Cakes & Frostings cups
Buttercream & Frosting Calculator
Work out how much frosting your cake needs, layer by layer: filling, crumb coat, final coat and decoration, for round or square layer cakes, sheet cakes and cupcakes. Then get the buttercream recipe scaled to match.
How to use it
- Choose what you're frosting and its size, layers and height.
- Pick the filling thickness, finish and decoration.
- Choose your frosting and make the scaled recipe shown, which includes 10% for the bowl and piping bag.
How it works
The calculator measures the cake: the area between layers for the filling, and the top and sides for a thin crumb coat (about 1/16 inch) and a final coat (about 3/16 inch for a smooth finish). Borders and piping are added from the cake's edge length.
With these thicknesses it matches Wilton's icing amounts for standard 4-inch-tall cakes: about 2½ cups for a 6-inch, 3½ for an 8-inch and 5 for a 10-inch. Recipes are scaled from tested base batches.
Assumptions and limits
- Coats are typical thicknesses; heavy piping, ruffles and textured finishes use more.
- Frosting weights depend on how much air you whip in.
- Cupcake amounts are per standard cupcake.
Tips
- Make 10 to 20% extra when piping something new; leftovers freeze for 3 months.
- Chill the crumb-coated cake 20 minutes before the final coat.
- Swiss meringue buttercream pipes beautifully and holds up in warm rooms.
Recipes to try it with
Questions
How much frosting do I need for a 2-layer 8-inch cake?
About 3¾ cups to fill and frost it smoothly, including a little extra for the bowl, and about 4¼ cups with top and bottom borders.
How much frosting for 24 cupcakes?
About 5 cups for a classic 3-tablespoon swirl, 3¼ cups for a flat spread and 6½ cups for tall bakery swirls, each with a little extra for the piping bag.
How much frosting does a 9x13 sheet cake need?
About 2¾ cups for a smooth top, 3¼ cups with a border, and about 5¼ cups if you frost the sides too.
How long does buttercream keep?
American buttercream keeps 2 weeks in the fridge and 3 months frozen. Re-whip it at room temperature before using.