Wedding cakes are cut in thin 1 × 2 inch slices, party cakes in larger 1.5 × 2 inch pieces. For more than about 60 wedding guests a single round cake gets impractically large, so tiered cakes or extra sheet cakes “in the kitchen” are common.
How to use the Cake Serving Calculator
- Number of guests
- Cake shape
- Slice size
- Difference between tier sizes
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the number of guests, the cake shape, the slice size and the difference between tiers.
Inputs explained
| Field | What to enter |
|---|---|
| Number of guests | A number |
| Cake shape | Choose one: Round, Square |
| Slice size | Choose one: Wedding (1 × 2 in), Party (1.5 × 2 in), Generous (2 × 2 in) |
| Difference between tier sizes | Units: in, cm |
What each result means
- Two tiers – top tier = [Two tiers – bottom tier] – [Difference between tier sizes]
- Full sheet cakes (18 × 24 in) = [Number of guests]×[Slice size]÷432
- Half sheet cakes (12 × 18 in) = [Number of guests]×[Slice size]÷216
- Quarter sheet cakes (9 × 13 in) = [Number of guests]×[Slice size]÷117
Example values
How the main result changes when Number of guests changes and everything else stays at the example values above:
| Number of guests | Single cake size (diameter or side) (in) |
|---|---|
| 50 | 11.3 |
| 75 | 13.8 |
| 100 | 16 |
| 125 | 17.8 |
| 150 | 19.5 |
| 200 | 22.6 |
Formula
Servings = top area × layers ÷ slice area (wedding slice 2 in², party 3 in², generous 4 in²; 4 in tall cake)
Round diameter = √(4 × guests × slice area ÷ π); square side = √(guests × slice area)
Two tiers (difference d): solve π/4 × (D² + (D − d)²) = needed area
Worked example
Inputs — Number of guests: 100; Cake shape: Round; Slice size: Wedding (1 × 2 in); Difference between tier sizes: 3 in.
Results — Single cake size (diameter or side) = 16 in; Two tiers – bottom tier = 12.7 in; Two tiers – top tier = 9.7 in; Full sheet cakes (18 × 24 in) = 0.46; Half sheet cakes (12 × 18 in) = 0.93; Quarter sheet cakes (9 × 13 in) = 1.71.
Frequently asked questions
How big a cake for 50 people?
About an 11–12 in round or two tiers of 6 and 10 in with wedding slices.
How many servings in a 9-inch round cake?
About 32 wedding slices or 20 party slices (4 in tall).
How many servings in a half sheet cake?
About 54 generous slices (2 × 2 in) or 108 wedding slices.