What Size Cake Do I Need for 15 People?

For 15 people, an 8-inch round cake serves about 20 party slices as two layers about 4 inches tall — the smallest single round that fits. Baked as one 2-inch layer it would serve only about 10. Every option is below.

15 people need

8-Inch Round

about 20 party servings (1½ × 2 in slice) as two layers, about 4 in tall · see every option below

Data & method: Serving counts from the published Wilton cake serving chart (two-layer cakes about 4 in tall; party 1½ × 2 in slice, wedding 1 × 2 in slice). Single-layer figures apply Wilton's rule that cakes under 3 in tall yield half (rounded down). The calculations are covered by automated tests. How we calculate →

Check any size or head count

Preset to 15 guests — the reverse lookup below the tiers finds the smallest fit.

Serving style

Tier 1 (or single cake)

+ Add tiers for a tiered or wedding cake

Tier 2 Tier 3 Tier 4

Serves about

party slices (1½ × 2 in)

Counts are for two layers about 4 in tall (3–6 in serves the same). One 2-inch layer per tier? About 10 (Wilton: under 3 in yields half).

Your cake, tier by tier

Next: how much frosting for this cake? →

Or plan backwards — how many guests?

We'll find the smallest two-layer cake that seats them, using the party/wedding slice size selected above.

Guests

An 8" round seats about 20 party servings — enough for 15.

Cake size for 15 people: every option

The chart below shows the smallest cake that covers 15 guests for each shape and slice size — all from the same Wilton figures the calculator uses. "Party" means a 1½ × 2 in slice; "wedding" a slimmer 1 × 2 in slice, which is why the wedding options run smaller. Counts are for two-layer cakes about 4 inches tall (Wilton: anything 3–6 inches tall serves the same); the last row is a single 2-inch layer, which Wilton says yields half.

Option	Smallest fit	Seats about
Round, party slices	8" round	20
Square, party slices	8" square	20
Round, wedding slices	8" round	24
Sheet, party slices	7×11" sheet	24
Sheet, single 2-in layer, party slices	9×13" sheet	18

A single cake covers this comfortably. If you'd rather make a moment of it, any two-tier combination whose counts add past 15 works — the calculator below totals tiers live as you pick them. Treat 15 as a minimum: end pieces and uneven cuts always cost a few servings, and leftover cake has never been a problem.

Ordering a sheet cake from a bakery? "Quarter", "half" and "full" sheet mean different sizes at different bakeries — the sheet cake sizes guide shows the usual dimensions and servings for each.

Cake ordered or planned? The frosting calculator and recipe scaler handle the baking side if you're making it yourself.

Nearby lookups

Cake Pan Converter

Convert any recipe between pan sizes — see both pans drawn to scale with batter fill levels, plus adjusted bake time and temperature.

Pan Volume Calculator

How much does your pan hold? Get the exact volume of any baking pan in cups, millilitres and litres, plus the batter it takes at a two-thirds fill.

Frosting Calculator

How much frosting does your cake need? Cups of buttercream by pan size, layers and coat thickness — computed from the cake's actual surface, with a cupcake swirl mode.