what size cake for 20 people

For about 20 people, a 9–10 inch (23–25 cm) round cake or an 8-inch tall/deep round cake is usually the safest single-tier choice, depending on slice size and how generous you want to be.

Quick Scoop

Recommended sizes for 20 guests

• Best all‑round pick:
  • 9–10 inch round cake (two or three layers) for standard “party” slices.

• If you like taller cakes:
  • 8 inch tall cake (about 6 inches high) can comfortably give 20–30 slimmer slices.

• If you prefer square or sheet cakes:
  • Roughly 8 inch square or a 9×13 inch quarter‑sheet can cover around 20–24 servings, depending on cut size.

How big should each slice be?

Most serving charts assume:

• Wedding / conservative slice: about 1×1 inch from a tall cake (more slices per cake).

• Party / dessert slice: about 1.5×2 inches from a tall cake (fewer, but more generous servings).

For 20 people at a birthday‑style party where cake is the main dessert, plan for party slices and a little buffer so you don’t run out.

Simple rule of thumb

• If cake is the main dessert → choose a 9–10 inch round or similar volume.

• If there will be lots of other desserts → an 8 inch round (especially tall) can be enough for 20.

Think: better to have a couple of extra slices than to tell the last guests, “Sorry, it’s gone.”

TL;DR:
Order a 9–10 inch round cake (or equivalent) for 20 people, especially if slices are decent‑sized and you want a tiny cushion for seconds.

Information gathered from public forums or data available on the internet and portrayed here.