Cake Servings Calculator

Calculate servings from a round, square, or sheet cake by size, layers, and slice style.
Covers wedding, party, and dessert portions for event planning.

The footprint of one slice. Layers change how tall a slice is, never how many there are.
Estimated Servings

How many people a cake feeds is a footprint question. Picture the top of the cake divided into a grid and count the rectangles. The height of the cake decides how big each slice feels, not how many of them there are, and that is the part everyone gets wrong.

Slice footprints

Style Slice Footprint
Wedding 1 × 2 in 2 sq in
Party 1.5 × 2 in 3 sq in
Dessert 2 × 2 in 4 sq in
Generous 2 × 3 in 6 sq in

Servings = cake area ÷ slice footprint

Stacking layers does not multiply that. Two 9-inch layers give the same number of slices as one 9-inch layer, each of them twice as tall. This is exactly what a wedding slice assumes: a 1 × 2 inch footprint on a 4-inch cake is 8 cubic inches, a real portion. The same footprint cut from a single 2-inch layer is half that, and it looks mean on the plate.

Worked example, 9-inch round

Area = π × 4.5² = 63.6 sq in Wedding slices: 63.6 ÷ 2 = 31 Party slices: 63.6 ÷ 3 = 21 Dessert slices: 63.6 ÷ 4 = 15

Published bakery charts put a two-layer 9-inch round at 32 wedding servings, so the arithmetic holds up against the industry numbers.

Round cakes at a glance

Diameter Area Wedding Party Dessert
6 in 28.3 sq in 14 9 7
8 in 50.3 sq in 25 16 12
9 in 63.6 sq in 31 21 15
10 in 78.5 sq in 39 26 19
12 in 113.1 sq in 56 37 28
14 in 153.9 sq in 76 51 38

Sheet cakes

Size Area Party Dessert Generous
9 × 13 117 sq in 39 29 19
11 × 15 165 sq in 55 41 27
12 × 18 216 sq in 72 54 36

Sheet cakes are nearly always a single 2-inch layer, which is why the wedding column is missing here. A 1 × 2 inch slice off a 2-inch sheet is a mouthful, not a serving. Party or dessert is the honest choice for a sheet.

Tiered cakes

Work out each tier on its own and add them up. If the top tier is being kept for the first anniversary, leave it out of the count entirely rather than promising cake you have already boxed.

The buffer. Add 10 to 15% to whatever number you land on. End pieces crumble, someone cuts the first few slices too generously, and there is always a second helping. Running out of cake in front of a room is a specific kind of misery.


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This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.

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