Cake Servings Calculator
Calculate servings from a round, square, or sheet cake by size and slice dimensions.
For wedding cakes, birthdays, and catering portion planning.
Cake serving size calculations depend on the cake shape, dimensions, and whether it is a dessert slice (smaller, richer cakes) or a party slice (larger, single-layer sheet cakes).
Standard Serving Dimensions:
- Party slice: 1 inch wide × 2 inches deep (finger food at large events)
- Dessert slice: 1.5–2 inches wide × 2 inches deep (seated dinner)
- Wedding cake: 1 inch wide × 2 inches deep (small — typically served with other food)
Round Cake Servings Formula:
Servings = π × r² / (Slice Width × 2)
For a 2-layer cake, multiply by 2 (since both layers count as one serving together).
Worked example — 9-inch round, 2-layer: r = 4.5 inches Area = π × 4.5² = 63.6 sq in At 1.5-inch party slice: 63.6 / (1.5 × 2) = 21 servings
Quick serving reference — standard round cakes (2 layers):
| Diameter | Party (1" slices) | Dessert (1.5" slices) |
|---|---|---|
| 6 inch | 12 | 8 |
| 8 inch | 20 | 14 |
| 9 inch | 24 | 18 |
| 10 inch | 38 | 26 |
| 12 inch | 56 | 40 |
Sheet cake servings (1-layer):
| Size | Party (2"×2") | Dessert (3"×2") |
|---|---|---|
| 9×13 | 24 | 12 |
| 11×15 | 35 | 18 |
| 12×18 | 54 | 27 |
Tiered wedding cakes: Calculate each tier separately, then sum. The top tier is traditionally saved for the first anniversary — subtract that tier from your count.
Planning buffer: Always calculate 10–15% extra servings at events — late arrivals, second helpings, and kitchen waste (end pieces, crumbled slices) consistently reduce actual portions.