About the Cake Serving Calculator
This cake serving calculator estimates how many slices you can cut from a cake of any size. Choose round, square, heart-shaped or rectangular sheet pans, enter up to three tier sizes, and pick the slice size you plan to cut: the small 1 × 2 inch slices used for wedding cakes, 1.5 × 2 inch party slices, or more generous 2 × 2 inch and 2 × 3 inch pieces.
It helps bakers quote the right cake for an order, couples planning a wedding or anniversary cake, and hosts deciding between a tiered cake and a sheet cake. Enter your guest count to see whether the cake is big enough and how many spare slices you will have.
Servings are calculated from the top area of each tier divided by the slice footprint, assuming a standard tier about 4 inches tall (two or three layers). Published bakery charts can be a little lower because round cakes lose some area to the curved edge when cut in a grid, so treat the result as a well-cut maximum and round down for casual cutting.
With the default inputs, the total servings is 78. Change any value above to recalculate instantly.
How to use the cake serving calculator
- 1Choose the pan shape.
- 2Enter each tier size, or the sheet cake length and width.
- 3Pick the slice size — wedding slices are the smallest.
- 4Enter your guest count to check the cake is big enough.
- 5Compare slice sizes in the table to fine-tune your order.
Formula and method
Each tier’s top area is calculated from the pan shape: π r² for round pans, side² for square pans, length × width for sheet cakes, and about 80% of a same-size square for heart pans. Dividing by the footprint of one slice — 2 sq in for a 1 × 2 in wedding slice, 3 sq in for a 1.5 × 2 in party slice — and rounding down gives the servings for that tier.
The method assumes tiers about 4 inches tall, which is the standard height behind bakery serving charts. Taller 5–6 inch tiers give more cake per slice rather than more slices. Round cakes cut in rings and wedges may yield a few slices fewer than the area method suggests.
- d
- Round pan diameter (in)
- s
- Square or heart pan side (in)
- Slice area
- Footprint of one slice in square inches
Worked examples
Three-tier round wedding cake (10, 8 and 6 in)
A 10 in round has 78.5 sq in of top area, giving 39 wedding slices of 2 sq in; the 8 in gives 25 and the 6 in gives 14. That is 78 servings, enough for 75 guests with 3 to spare.
9 × 13 sheet cake with party slices for 30 guests
A 9 × 13 in sheet has 117 sq in of top area. At 3 sq in per 1.5 × 2 in party slice you get 39 servings — 9 more than you need.
Two-tier square cake (12 and 8 in) for 100 guests
Square tiers use their full area: 144 sq in ÷ 2 = 72 wedding slices from the 12 in tier and 64 ÷ 2 = 32 from the 8 in tier, 104 in total.
Frequently asked questions
How many servings are in an 8 inch round cake?+
An 8 inch round cake about 4 inches tall gives roughly 24–25 wedding-size slices (1 × 2 in) or about 14–16 party slices (1.5 × 2 in). Cut in traditional wedges, most people get 8–12 generous slices.
What size cake do I need for 100 guests?+
For about 100 wedding-size servings, a three-tier round cake of 12, 9 and 6 inches or 12, 8 and 6 inches works well (about 95–100 slices). A square 12 and 8 inch two-tier cake gives about 104 wedding slices.
How many people does a 9x13 sheet cake feed?+
A 9 × 13 inch sheet cake gives about 39 party-size slices (1.5 × 2 in), 29 generous 2 × 2 in squares or about 19 large 2 × 3 in pieces. A half sheet (roughly 12 × 18 in) gives about 72 party slices.
Why are wedding cake slices smaller than party slices?+
Wedding cake is usually served after a full meal and cut from tall tiers, so bakers plan a slim 1 × 2 inch slice about 4 inches tall. Party slices are 1.5 × 2 inches because cake is often the main dessert.
Does a taller cake give more servings?+
Not more slices, but bigger ones. Serving charts assume tiers about 4 inches tall; a 6 inch tall tier gives the same number of slices, each with about 50% more cake, unless you cut it into two shorter servings.