Planning
Cake serving guide: what size cake do I need?
Servings decide almost everything else about a cake, including the tiers, the shape and the price. Use this cake size guide to work out the number first, and every conversation afterwards gets easier.
- Typical industry ranges
- Round and tiered
- Party and wedding portions
Count the guests who will actually take a slice, then choose the tin size that covers that number using the portion style you intend to cut. As a rule of thumb, a 20 cm round covers a family birthday, a 25 cm round covers a large party, and anything over about 60 guests is usually easier as two tiers or as a cutting cake plus a kitchen cake.
First, choose your portion
The same cake serves two very different numbers
Before any chart is useful, decide how the cake is being cut. This single decision changes the serving count by roughly half.
Wedding portions are cut as small finger slices, traditionally about 2.5 cm square across the face of the cake. They are served on a plate or a napkin, often with coffee, and they assume the cake is one part of a longer evening.
Party or dessert portions are roughly twice as wide, because the cake is the dessert. Use these for birthdays, kids parties and any celebration where cake is the sweet course rather than a tradition.
Every cake maker portions slightly differently, so treat the numbers below as typical ranges and confirm the serving count in your quote.
Single tier
Round cake sizes and typical servings
Based on a finished tier around 10 cm (4 in) high. Square tins of the same measurement generally yield around a quarter more.
| Round tin | Wedding portions | Party portions | Typically suits |
|---|---|---|---|
| 15 cm (6 in) | 12 to 14 | 8 to 10 | A cutting cake, a smash cake or a small gathering |
| 20 cm (8 in) | 20 to 24 | 14 to 16 | A family birthday or a small celebration |
| 23 cm (9 in) | 27 to 32 | 18 to 22 | A mid sized party |
| 25 cm (10 in) | 35 to 40 | 24 to 28 | A large party or a small wedding |
| 30 cm (12 in) | 50 to 56 | 36 to 40 | A large celebration or a tier base |
| 35 cm (14 in) | 70 to 78 | 50 to 56 | A base tier on a large wedding cake |
Tiered cakes
Common tier combinations
Height and servings are separate decisions. A tall cake does not always feed more people, and a dummy tier feeds nobody at all.
| Structure | Tier sizes | Wedding portions | Party portions |
|---|---|---|---|
| Two tier | 15 cm + 20 cm | 32 to 38 | 22 to 26 |
| Two tier | 20 cm + 25 cm | 55 to 64 | 38 to 44 |
| Three tier | 15 cm + 20 cm + 25 cm | 67 to 78 | 46 to 54 |
| Three tier | 20 cm + 25 cm + 30 cm | 105 to 120 | 74 to 84 |
| Four tier | 15 cm + 20 cm + 25 cm + 30 cm | 117 to 134 | 82 to 94 |
Three ways to stretch a cake
When the design you love does not feed the room
Add a kitchen cake
A plain slab in the same flavour, cut out of sight and plated with the rest. The cheapest way to add servings without touching the design.
Add a dummy tier
A decorated polystyrene tier that gives height for the photographs. Costs decoration time instead of cake, and feeds nobody.
Switch round to square
Roughly a quarter more portions from the same nominal size. Often enough to clear a serving threshold without going up a tier.
Common questions
Cake sizes and servings
What size cake do I need for 50 guests?
For 50 guests, a 25 cm (10 in) round cut into wedding portions typically reaches 35 to 40 slices, so it is a little short. Three options usually work. A 30 cm (12 in) round gives roughly 50 to 56 wedding portions. A two tier 15 cm and 25 cm combination lands in a similar range with more height. Or keep a smaller cutting cake for the photos and add a plain kitchen cake cut in the back, which is often the cheaper answer.
What size cake do I need for 100 guests?
For 100 guests in wedding portions, a three tier cake of 20 cm, 25 cm and 30 cm tiers lands at roughly 105 to 120 portions, which is the usual answer. In larger dessert portions the same cake reaches about 74 to 84, so it would not stretch. A four tier cake adds height rather than a large number of extra servings. If the design you want is smaller than the room, a kitchen cake cut out of sight is the standard and least expensive fix.
What is the difference between a party portion and a wedding portion?
Portion size, not cake size. A wedding portion is traditionally cut as a small finger slice, roughly 2.5 cm by 2.5 cm across the face of the cake. A party or dessert portion is around twice that width, because it is being eaten as dessert over handed around with coffee. The same cake can honestly be described as serving 40 or 24 depending on which one you are counting.
Do square cakes serve more than round?
Yes, for the same nominal size. A square tin has more surface area than a round one of the same measurement, so it commonly yields around a quarter more portions. If you are close to a serving threshold, switching to square can be a cheaper answer than going up a size.
How tall is a standard cake tier?
Most Australian serving charts assume a finished tier around 10 cm (4 in) high, made from layered sponge and filling. Taller tiers are increasingly common and change the numbers, so if you are quoted a double height or extended tier, ask for the serving count rather than assuming.
Should I count children as full servings?
Usually not. Many people count children as half a serving, and count on some adults not taking a slice at all when there is a dessert table or a late reception. Tell your cake maker the guest breakdown ahead of adjusting the number yourself, so the recommendation is theirs to stand behind.
What if the cake I love does not feed the room?
Two standard solutions, and neither is a compromise. Add a dummy tier for height and serve from the real ones, or add a plain kitchen cake cut out of sight. Both let you keep the design and the photograph while still feeding everybody.
You have your number
Put it in your cake brief
Servings, date, suburb and style. That is everything a cake maker needs to quote you properly.