Cake Calculator
The sheet size, round-cake combo, or cupcake count your guest list actually needs — using the same serving charts bakeries quote from.
You need
Enter guest count
| Options that work | Details |
|---|---|
| Sheet cake | — |
| Round cakes | — |
| Cupcakes | — |
Grocery sheet cakes run $0.75–$2/serving; custom bakery $3–$8+.
How Cake Sizing Works
Bakeries size cakes in servings, not diameters — and the serving is a defined slice:
- Party cut: ~1.5″ × 2″ slice — the birthday standard.
- Wedding cut: ~1″ × 2″ — slimmer because it follows a full meal; the same cake serves 20–40% more.
- Match servings to guests, then add margin only if cake is the sole dessert.
Standard Cake Serving Chart
| Cake | Party servings | Wedding servings |
|---|---|---|
| 6″ round | 12 | 14 |
| 8″ round | 20 | 24 |
| 10″ round | 28 | 38 |
| 12″ round | 40 | 56 |
| Quarter sheet (9×13) | 24 | 32 |
| Half sheet (13×18) | 48 | 64 |
| Full sheet (18×26) | 96 | 128 |
Two-layer rounds; single-layer sheets. Charts vary slightly by bakery — always confirm against theirs for a paid order.
Servings by Guest Count
One party-cut slice per guest — the sheet, round and cupcake options for the same crowd: Every row is the calculator above at its default settings.
| Guests | Servings | Sheet cake | Round cakes | Cupcakes |
|---|---|---|---|---|
| 10 | 10 | 1 quarter sheet (24) | one 6″ (12) | 11 (1 each + 10%) |
| 15 | 15 | 1 quarter sheet (24) | one 8″ (20) — or 6″ + 6″ (24) | 17 (1 each + 10%) |
| 20 | 20 | 1 quarter sheet (24) | one 8″ (20) — or 6″ + 6″ (24) | 22 (1 each + 10%) |
| 25 | 25 | 1 half sheet (48) | one 10″ (28) — or 8″ + 6″ (32) | 28 (1 each + 10%) |
| 30 | 30 | 1 half sheet (48) | one 12″ (40) — or 10″ + 6″ (40) | 33 (1 each + 10%) |
| 40 | 40 | 1 half sheet (48) | one 12″ (40) — or 10″ + 6″ (40) | 44 (1 each + 10%) |
| 50 | 50 | 1 full sheet (96) | 12″ + 6″ (52) | 56 (1 each + 10%) |
| 75 | 75 | 1 full sheet (96) | 12″ + 12″ (80) | 83 (1 each + 10%) |
| 100 | 100 | 1 full sheet + 1 quarter sheet (24) | multiple 12″ rounds | 111 (1 each + 10%) |
| 150 | 150 | 1 full sheet + 1 full sheet (96) | multiple 12″ rounds | 165 (1 each + 10%) |
| 200 | 200 | 2 full sheets + 1 quarter sheet (24) | multiple 12″ rounds | 221 (1 each + 10%) |
Tips Before You Order
- Kitchen cakes save money at scale: a small decorated display cake plus a plain sheet cut in back serves a crowd at grocery-cake prices.
- Cupcakes trade cutting for counting — no knife, no plates, but order 10% over and display on tiers so the table never looks empty.
- Cold cakes cut cleaner. Chill before cutting, wipe the knife between slices, and a half sheet takes one person about 10 minutes.
- If cake competes with other desserts, plan servings for ~75% of guests instead of 100%.
Frequently Asked Questions
What size cake for 30 guests?
A half sheet (48 party servings), or a 10″ + 6″ round combo (40), or ~33 cupcakes.
How many does a full sheet feed?
~96 party servings (18×26″); half sheet ~48; quarter ~24.
Servings in an 8″ round?
About 20 party or 24 wedding servings for two layers.
Party vs wedding servings?
Party slices are 1.5″×2″; wedding slices 1″×2″ — same cake, 20–40% more servings.
Cupcakes per guest?
1 per guest + 10%; 1.5 per child at kids' parties.
What's a kitchen cake?
An undecorated back-of-house sheet cake served alongside a small display cake — same servings, lower price.
What size cake do I need for 20 people?
For 20 guests at one party-cut slice each you need 20 servings: 1 quarter sheet (24) as a sheet cake, one 8″ (20) — or 6″ + 6″ (24) as rounds, or 22 (1 each + 10%) cupcakes. Wedding-cut slices are smaller, so a wedding cake for the same crowd can be a size down.
What size cake do I need for 50 people?
For 50 guests at one party-cut slice each you need 50 servings: 1 full sheet (96) as a sheet cake, 12″ + 6″ (52) as rounds, or 56 (1 each + 10%) cupcakes. Wedding-cut slices are smaller, so a wedding cake for the same crowd can be a size down.
What size cake do I need for 100 people?
For 100 guests at one party-cut slice each you need 100 servings: 1 full sheet + 1 quarter sheet (24) as a sheet cake, multiple 12″ rounds as rounds, or 111 (1 each + 10%) cupcakes. Wedding-cut slices are smaller, so a wedding cake for the same crowd can be a size down.
References
- Wilton — cake serving charts and cutting guides: wilton.com
- The Knot — wedding cake sizing conventions: theknot.com
- King Arthur Baking — pan sizes and yields: kingarthurbaking.com
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