Cake servings calculator

Estimate how many party portions a round cake gives by diameter — or work backwards from your guest count to the smallest cake that covers everyone.

Round cake diameter (in)

Result

Party servings

How to use this tool

Servings from a size: choose the cake's diameter.
Size from a guest count: switch direction and enter the number of guests.
For a tiered cake, add up the servings of each tier.

Assumptions

Party-cut portions are narrow slices. As a planning rule of thumb, dessert-plate slices give roughly half as many — not a measured figure.
The table is an illustrative convention, not an industry-wide bakery standard; cut style and cake height change the real count.

Technical details: what the fields mean

Round cake diameter diameterIn: The cake's diameter in inches — check the size ordered or the tin used. 6in ≈ 15cm, 8in ≈ 20cm, 10in ≈ 25cm, 12in ≈ 30cm, 14in ≈ 35cm.

Methodology

Looks up PracticalBench's party-portion table for a single-layer-height round cake: 6in = 11, 8in = 20, 10in = 31, 12in = 45, 14in = 61. Working backwards picks the smallest size whose count covers your guests, or several 14in cakes beyond 61.

Worked example

10-inch round cake

Inputs: Round cake diameter: 10 in

Result: 31 party portions; plan on roughly 15 if you cut dessert-size slices.

What size for 25 guests?

Inputs: Number of guests: 25

Result: A 10-inch cake (31 portions) — an 8-inch gives only 20.

What size for 100 guests?

Inputs: Number of guests: 100

Result: Two 14-inch cakes (122 portions) — or a tiered cake: 6 + 8 + 10 + 12 + 14 inch tiers give 11 + 20 + 31 + 45 + 61 = 168.

A three-tier 6/8/10-inch wedding cake

Inputs: Round cake diameter: 6, 8 and 10, added together

Result: 11 + 20 + 31 = 62 party portions.

Practical guidance

Decide the cut before ordering: party portions suit a buffet or wedding, dessert slices suit a sit-down meal.
If the cake is the dessert, use the dessert-slice estimate; if there's another dessert, party portions are usually enough.
Confirm the count with the bakery for a paid event — their cake height and cutting guide may differ.

Common mistakes

Ordering by party-portion count but cutting dessert-size slices, which runs out at about half the guests.
Forgetting the top tier of a wedding cake is often kept, so it shouldn't count towards serving guests.

FAQs

How many party servings does a 10-inch round cake give?

31 with this tool's party-cut table; plan on roughly half that for dessert-size slices.

What size cake do I need for 50 people?

A 14-inch round (61 party portions), or a two-tier 8 + 12 inch cake (65).

How do I count servings for a tiered cake?

Look up each tier's diameter and add them together. Leave out any tier you plan to keep.

Last reviewed: 2026-10-11

A lookup estimate for round cakes; actual servings depend on cake height, cut size and serving style.

This tool provides an indicative estimate, based on the assumptions stated above.

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