How to Choose the Right Size Celebration Cake

Choosing the right cake size is one of the most common questions people ask when ordering a celebration cake. Whether you're planning a birthday party, baby shower, anniversary, or office event, getting the right size cake ensures everyone gets a slice.

The size of cake you need depends on a few key factors, including how the cake will be served, how many guests you're expecting, and the style of cake you choose.

This guide will help you understand cake portions, serving sizes, and how tall cakes often provide more servings than people expect.

If you're currently exploring options, you can browse our custom celebration cakes here.

Most celebration cakes are chosen based on the number of guests. As a general guide, a 6 inch cake serves around 10–12 dessert portions or 12–20 party portions, while an 8 inch cake can serve around 20–24 dessert portions or up to 36 party portions.

Dessert Portions vs Party Portions

One of the biggest factors when choosing cake size is how the cake will be served.

There are two main portion styles.

Dessert Portions

Dessert portions are larger slices and are usually served as the main dessert after a meal.

These are common for:

• Dinner parties

• Weddings

• Celebrations where cake is the primary dessert

A typical dessert portion is around 2 inches by 2 inches.

Party Portions

Party portions are smaller slices and are used when cake is served alongside other food or desserts.

These are common for:

• Birthday parties

• Office celebrations

• Baby showers

• Events with buffets or dessert tables

Party portions are usually around 1 inch by 2 inches. Because party portions are smaller, the same cake can serve many more guests.

How Many Servings Different Cakes Provide

Below is a general guide to how many portions typical celebration cakes provide.

At Kimmi’s Cakes, celebration cakes are usually around 6 inches tall, made with three layers of sponge and filling, which means they serve more portions than many standard cakes.

Typical Celebration Cake Serving Guide

6 inch round cake - Party portions: 12–20 | Dessert portions: 10–12

7 inch round cake - Party portions: 16–28 | Dessert portions: 14–18

8 inch round cake - Party portions: 24–36 | Dessert portions: 20–24

9 inch round cake - Party portions: 32–48 | Dessert portions: 26–32

Round Cakes vs Tall Cakes

Not all cakes provide the same number of servings.

Traditional cakes are often shorter with only two layers of sponge, typically around 3 to 4 inches tall.

Modern celebration cakes, however, are often much taller, usually around 6 inches high with three layers of sponge.

These taller cakes:

• Provide more servings

• Look more impressive on a table

• Allow for more filling and flavour combinations

Tall cakes have become the most popular option for birthdays and celebrations because they offer both visual impact and generous portions.

Example Cake Sizes for Different Events

Here are some examples to help you decide what size cake may suit your celebration.

Small Gatherings (10–15 guests)

A 6 inch cake is usually ideal.

Perfect for:

• Small birthday celebrations

• Dinner parties

• Family gatherings

Medium Celebrations (20–30 guests)

A 7 inch or 8 inch cake works well.

Great for:

• Adult birthdays

• Baby showers

• Engagement parties

Larger Celebrations (35+ guests)

A larger cake or two tier cake may be the best option.

Ideal for:

• Milestone birthdays

• Corporate celebrations

• Large family events

When It’s Worth Choosing a Larger Cake

Sometimes choosing a slightly bigger cake is the best option.

You may want to size up if:

• Cake will be the main dessert

• You expect guests to want larger slices

• You want leftovers

• The design requires more space for decorations

Choosing a slightly larger cake also allows for more design flexibility and a stronger visual centrepiece for your event.

Choose Your Cake Flavour

Once you’ve decided on the right cake size for your celebration, the next step is choosing your flavour.

From classic vanilla sponge to richer chocolate and fruit combinations, there are plenty of options to suit different tastes and occasions.

You can explore the full list of cake flavours here.

Browse Celebration Cakes

If you're planning a birthday, baby shower, or special celebration and would like a bespoke cake designed for your event, you can browse cake designs and submit an enquiry through the website.

Browse Custom Celebration Cakes

Each cake from Kimmi's Cakes is made to order and designed specifically for your celebration, ensuring the perfect balance of flavour, style, and portion size.

Enquire About a Celebration Cake

Cake Size FAQs

What size cake do I need for 20 people?

For around 20 guests, a 7 inch or 8 inch celebration cake usually works well. A tall 7 inch cake can serve around 16–28 party portions, while an 8 inch cake can provide 24–36 party portions, depending on how the cake is sliced.

How many servings does an 8 inch cake provide?

An 8 inch celebration cake typically serves:

• 24–36 party portions• 20–24 dessert portions

Tall cakes with three layers of sponge can often provide more servings than standard cakes.

What size cake do I need for 30 guests?

For around 30 guests, an 8 inch celebration cake is usually a good option if serving party portions.If cake will be served as the main dessert, you may want to consider a larger cake or a two-tier cake.

Are tall cakes better for larger parties?

Yes, tall celebration cakes provide more servings because they contain additional sponge and filling layers.They also create a more impressive centrepiece for birthdays and celebrations.