What size cake for how many guests? A planner by occasion

Short answer: for a wedding (1"×2" portions) an 8" round covers 20 guests, 8"+10" covers 50, 6"+8"+10" covers 75, 8"+10"+12" covers 100 and 10"+12"+14" covers 150. For a birthday (1.5"×2" portions) the same cakes serve fewer, so you move up: 8" for 20, 8"+10" for 45, 8"+10"+12" for 85, and 10"+12"+14" for 120.

Two numbers decide everything on this page: the guest count and the portion size. Get the portion wrong and a cake sized for 100 feeds 70. The full grid of sizes and portions is on the cake serving size chart; this page turns it into a decision.

Cake size by guest count

All round tiers, standard height, stepped 2 inches apart.

Every Serves figure is at or above the guest count, so you can read the headroom directly — a 50-guest wedding cake built as 8" + 10" has twelve slices spare, which is about right once you lose two to a bad first cut and one to the couple.

Where the headroom looks large, the alternative is usually a smaller stack plus a kitchen cutting cake, or a tall tier (see below) rather than a wider one.

The full tier reference

If the combination you need is not in the table above, here is every standard stack:

Weddings

Use the 1"×2" wedding portion. It is what a caterer will cut, it is what the venue expects, and it yields roughly 20% more slices than a party portion — which is the whole reason the convention exists.

Three things that change the number:

• The top tier is often kept. For an anniversary, or frozen for a christening. If it is, take it out of the count before you quote: a 6"+8"+10" that serves 76 serves 62 once the 6" goes home in a box.
• A dummy tier serves nobody. A couple who want the height of a four-tier cake on a 60-guest budget can have a polystyrene base tier. It is a legitimate and common choice — just make sure the serving count on the quote describes only the real tiers.
• Cutting cake. Some venues cut a plain sheet cake in the kitchen and serve it alongside the display cake. If the venue is doing that, the display cake does not need to feed everyone.

Do you size down for guests who will not eat cake? Bakers differ, and both positions are defensible. Not reducing is the safer professional choice: cake is served late, plates get shared, and a couple who run out in front of 120 guests will remember it for a long time. If you do reduce, do it at the customer's explicit instruction and write it on the quote.

Birthdays and family parties

Use the 1.5"×2" party portion — the slice people actually expect at a birthday.

The practical difference from a wedding is that the cake is usually the dessert, not an extra course after one. That argues for the generous end of the range rather than the tight one. For 30 guests a 12" round at 40 party portions leaves room for seconds and a slice for the host; an 11" at 30 is exactly enough and exactly enough is uncomfortable.

For children's parties the opposite is often true: small hands, small appetites, and half the cake goes home in napkins. A dessert portion count (2"×2") is frequently closer to reality than a party portion, so a 10" round billed as 19 servings will usually stretch over 25 children.

Corporate and office orders

These are the orders most often sized wrong, because the guest count is a headcount and the attendance is not.

Three rules that hold up:

1. Price and size against the headcount, not the RSVP. An office of 60 orders for 60 even though 45 will be at their desks.
2. Expect finger portions. Cake handed out in a meeting room with no plates gets cut small — 1"×1" or 1"×2". A 12" round at 112 finger portions covers a surprisingly large office.
3. Sheet and slab beat tiers. Nobody photographs a corporate cake from the side. A slab is faster to make, cheaper to deliver, trivial to cut, and serves more per dollar.

Christenings, baby showers and small gatherings

Usually 20–40 guests with a single-tier or two-tier cake, cut at party portions — so an 8" for 20, a 6"+8" for 29, or a 12" for 40.

The thing to clarify is whether there is a dessert table. If there is, the cake becomes one item among several and a finger portion is right, which roughly halves the size needed.

Dessert tables: how much cake do you actually need?

When the cake sits alongside tarts, cookies and macarons, nobody eats a full slice. Size the cake for the role it is playing:

• Cake as the only dessert → 2"×2" dessert portions. A 10" round serves 19.
• Cake as the centrepiece of a dessert table → 1"×2" or 1"×1". A 10" round serves 38 or 76.
• Cake as one item among six → 1"×1" finger portions, and expect leftovers.

A useful way to put it to a customer: "Do you want everyone to be able to have a slice, or everyone to be able to try it?" The two answers are different cakes.

Why tiers are stepped 2 inches apart

Because less than that does not read as a tier. A 10" sitting on a 12" looks like a mistake; a 10" on a 14" looks deliberate but wastes serving capacity in the gap. Two inches is the convention for a reason, and it is why the serving counts for 6+8+10 and 8+10+12 are the two most quoted numbers in the trade.

A tier can also be tall or double-barrel, which doubles the servings from that tier at the same footprint. It is the cheapest way to add servings without widening the cake — an 8" tier goes from 20 party portions to 40 — and it costs twice the batter, which belongs in the price.

Before you quote, subtract these

• The top tier, if it is being kept.
• Any dummy tiers.
• Whatever the venue's kitchen cutting cake covers.
• The slices you will lose to a bad first cut — one or two on a tiered cake, routinely.

And add the one thing people forget: a slice for the couple or the host, who otherwise watch their own cake disappear.

Frequently asked questions

What size cake do I need for 50 guests?
At wedding portions, an 8" + 10" two-tier serves 62. At party portions, a 14" round serves 56 or a 10" + 12" serves 68. Size up rather than down if the cake is the only dessert.

What size cake for 100 guests?
At wedding portions, an 8" + 10" + 12" three-tier serves 118, or a single 16" round serves exactly 100. At the larger party portion you need 10" + 12" + 14", which serves 124.

What size cake for 30 guests?
A 10" round serves 38 at wedding portions. At party portions a 12" round serves 40, or a 6" + 8" two-tier serves 29 — tight for 30, so the 12" is the safer quote.

How many tiers do I need for 120 guests?
Three at wedding portions — 10" + 12" + 14" serves 172, or 6" + 8" + 10" + 12" serves 132 if you want four. At party portions 10" + 12" + 14" serves 124, which fits 120 almost exactly.

Should I count guests who will not eat cake?
Most bakers do not reduce for them. Cake is served late, plates get shared, and running short in front of a full room is far worse than a few slices left over. If a customer asks you to size down, do it on their instruction and record it on the quote.

Does keeping the top tier change the serving count?
Yes, and it is easy to miss. A 6" + 8" + 10" serving 76 wedding portions serves 62 once the 6" top tier goes home with the couple. Subtract it before you quote.

What size cake for a dessert table?
Roughly half what you would make if the cake were the only dessert. Size it at 1"×1" or 1"×2" portions rather than 2"×2" — a 10" round serves 76 as finger portions against 19 as dessert slices.

Is a sheet cake better than a tiered cake for an office order?
Usually. Corporate cake is cut small, served without plates and never photographed from the side, so a slab is faster to make, cheaper to deliver, easier to cut and serves more per dollar than tiers.

Quote it without the arithmetic

Bake Boost has this built in: enter the tiers, pick the portion size, tick the tall tiers, and it gives you the serving count, a printable cutting diagram for the venue, and the price at your own per-serving rate. On every plan.

See the full cake serving size chart, work out what to charge once you know the count, or look up a term in the bakery costing and pricing glossary.