Packaging guide
Cake Box Sizes in Inches and Millimetres, and the Board That Fits
Which box and board fit a 6, 8, 10 or 12 inch cake, how tall to go and what cupcake inserts measure.
Why are cake boxes still sold in inches?
Cake tins in the UK are sold in inches, so cakes are baked in inches and the boxes followed. A 6 inch cake is 150 mm across, an 8 inch is 200 mm, a 10 inch is 250 mm and a 12 inch is 300 mm.
The box, though, is not sized from the cake. It is sized from the board the cake sits on, and the board is almost always bigger than the cake. Miss that step and the box is an inch too small.
Round and square cakes use the same table. A square 8 inch cake sits on a square 10 inch board and needs the matching square box. A round cake on a round board goes in the same square box with the corners spare. Heart and hexagon boards follow the square rule.
This guide gives the box and board for each common cake size, the height to ask for and what cupcake boxes measure. Everything is in both units so you can order either way.
Which box fits a 6, 8, 10 or 12 inch cake?
The usual rule is board two inches bigger than the cake, box the same size as the board. So a 6 inch cake sits on an 8 inch board and goes into an 8 inch box.
The table gives the inside box size for each step. Heights are for a standard two or three layer sponge with buttercream. Taller cakes are covered in the next section. The printed cake boxes with lids are cut to any of these inside sizes.
| Cake | Board | Inside box footprint | Inside height |
|---|---|---|---|
| 6 inch (150 mm) | 8 inch (203 mm) | 205 × 205 mm | 100 to 125 mm |
| 7 inch (178 mm) | 9 inch (229 mm) | 230 × 230 mm | 100 to 125 mm |
| 8 inch (203 mm) | 10 inch (254 mm) | 255 × 255 mm | 125 to 150 mm |
| 9 inch (229 mm) | 11 inch (279 mm) | 280 × 280 mm | 125 to 150 mm |
| 10 inch (254 mm) | 12 inch (305 mm) | 305 × 305 mm | 150 mm |
| 12 inch (305 mm) | 14 inch (356 mm) | 355 × 355 mm | 150 to 175 mm |
How does the cake board change the box?
The board sets the footprint and adds to the height. A thin card board is about 3 mm thick. A drum board is about 12 mm. Both need to be added to the cake height when you choose the box.
Boards also need a finger gap. If the board is exactly the inside size of the box, nobody can lift it out without tipping the cake. Allow 2 to 3 mm each side, which is why the table shows 205 mm for an 8 inch board.
Some bakers use a board the same size as the cake for drip cakes and semi-naked styles. Then the box can be smaller, but the cake has no edge to hold. The cake boards in matching sizes are cut to pair with the boxes.
How tall should a cake box be?
Measure the finished cake from the bottom of the board to the top of the highest decoration. Then add 10 mm so the lid does not touch the icing.
A three layer 8 inch sponge with buttercream is about 110 mm tall. On a 12 mm drum that is 122 mm, so a 150 mm box fits with room for a topper. A four layer cake with a drip and tall decorations can reach 180 mm.
Standard cake boxes are often 100 or 150 mm tall. Above that you want a taller style. The tall cake boxes for layered cakes run to 200 mm and more, with the same footprints as the table above.
Fridge height is the limit most bakers forget. A domestic fridge shelf is often 150 to 170 mm tall, and a 200 mm box will not go in without taking a shelf out. If the customer is storing the cake overnight, tell them the box height when they order.
What sizes do cupcake boxes and inserts use?
Cupcake boxes are sized by count, not by inches. Six and twelve are the common counts, with four and twenty four for smaller and larger orders.
The insert is the important part. A standard cupcake case is about 50 mm across the base and 70 mm across the top once baked. An insert hole of 55 to 60 mm holds the case firmly without crushing it. Large muffin cases need 65 to 70 mm holes.
A six hole box with inserts is usually about 250 × 170 × 80 mm inside. A twelve hole box is about 330 × 250 × 80 mm. The cupcake boxes with inserts come with the insert matched to your case size.
How do you measure a decorated cake?
A ruler across the top is not enough. Decorations, drips and boards all add to the number. Here is the order that gives a box size that works first time.
- Measure the board, not the cake, across its widest point.
- Add 2 to 3 mm each side for a finger gap and write that down as the footprint.
- Stand the cake on its board and measure from the table to the highest decoration.
- Add 10 mm so the lid clears the top, and 20 mm if you use tall toppers.
- Check whether the box has to fit in your fridge shelf before you fix the height.
- Send both numbers in millimetres and say what the cake is, so we can sanity check them.
Should you choose a handle, a window or a plain lid?
A plain lidded box is the cheapest and stacks best. A window lid shows the cake without opening the box, which helps at a counter or a market. A handle makes a heavy cake easier to carry but takes more board.
For a 10 inch or bigger cake, weight matters more than looks. A three layer 10 inch cake on a drum board can pass 3 kg. That wants a box with a base that locks and a handle that is part of the structure, not glued on.
The cake carrier boxes with handles are built for that weight, and they can still take a window in the lid.
Cold cakes also sweat. A chilled cake in a sealed box at room temperature fogs the window and softens the board. Leave the box open for ten minutes after the cake comes out of the fridge, then close it for the journey.
What are the common cake box sizing mistakes?
Most cake box problems come from one of five habits. All of them are easy to catch before the order goes in.
The most common is ordering by cake size and forgetting the board. The second is ordering one height for every cake, so the tall cakes get crushed and the short ones look lost.
- Sizing the box from the cake instead of the board
- Forgetting the 12 mm a drum board adds to the height
- No finger gap, so the board jams in the box
- One height for every cake on the menu
- Ordering a window box for a cake that goes in a fridge, where the window steams up
How do slices and single portions size up?
A slice box is sized from the slice, which is a wedge rather than a square. A slice from an 8 inch cake is about 100 mm long, 60 to 70 mm wide at the back and as tall as the cake.
A common inside size is 110 × 80 × 90 mm for a standard slice. A tall slice with a drip wants about 130 × 90 × 110 mm. Brownies and traybake squares use a shallower box, often 100 × 100 × 50 mm.
If you sell by the slice at a counter, a window on the slice box lifts sales. The single cake slice boxes can take a window on the lid or the front.
How do you order cake boxes to your sizes?
Send us your cake sizes, board sizes and finished heights, plus your logo. We send a free design proof for each box, and nothing is printed until you approve it.
A written quote starts at £0.25 per unit and covers the quantity you ask for. Food-contact materials available on request, confirmed on that quote. From proof approval, the boxes take 4 to 6 business days to make, and the tracked UK delivery is free and takes 2 to 3 business days.
Order before the wedding and birthday season fills your diary, and keep the box sizes in step with your tins. The cake and cupcake box range lists every style we make.
