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Cake Serving Calculator
What size cake you need for your guest count — round or square, one tier or two, party slices or dessert slices.
Your results
Cake size needed
25 cm (10 in)
Servings that size gives
35
Or two tiers of
20 cm
Buttercream needed
1.20 kg (2.6 lb)
A 23 cm (9-inch) round, two layers, gives about 28 party slices — the thin, tall wedges a caterer cuts. Cut it as dessert and the same cake feeds eighteen. Decide which you are serving before you decide the size, because the difference is a third of the cake.
A square tin holds about 27% more than a round one of the same width, because you are not throwing away the corners. If you are feeding a crowd from one tin, square is the more efficient shape and always has been.
Two smaller tiers beat one enormous tin. A 35 cm cake bakes unevenly — the edges are dry before the middle sets — while two 25 cm layers bake in the same oven, in the same time, and stack into something that looks like it took more effort than it did.
Questions people ask
What size cake for 30 people?
A 25 cm (10-inch) round, two layers, cut into party slices. If cake is the only dessert, go to 30 cm or make two 23 cm tiers.
How many does a 9-inch cake serve?
About 28 as party slices, or 18 as dessert portions. Two layers assumed — a single layer is half of that.
How much buttercream for a layer cake?
About 40 g per serving covers filling, crumb coat and finish. A 23 cm two-layer cake takes roughly 1 kg to fill and cover properly.