You've spent six hours on a cake. The layers are level, the buttercream is smooth, and the piping is the best you've ever done. Then you close the box and hear the lid meet the rosettes. Or it fits perfectly, and slides into the corner at the first roundabout.

A cake box is the cheapest part of the whole project, and the part most likely to ruin it. The good news is that choosing the right one comes down to two measurements, and neither of them is the size of your cake.

Here is the full guide: which box suits which cake, how much room to leave for tiers, buttercream and toppers, and how to get it all from your kitchen to the party in one piece.

The Short Answer

If you want to skip straight to the box, here is the quick version. This assumes a standard two-layer cake around 10cm tall, sitting on a board 5cm wider than the cake.

Still not sure? Size up in height, never in width. Extra headroom costs you nothing. Extra width gives the cake room to slide.

Measure the Board, Not the Cake

This is the mistake almost everyone makes once. A cake box is sized by the board it holds, not the cake sitting on top.

Our standard boxes say it right on the label: a 10 inch box holds a 10 inch square or round cake board. So a 20cm cake on a 25cm board needs a 10 inch box. Buy an 8 inch box to match the cake, and the board won't go in.

The board itself should be around 5cm wider than the cake. That gives you 2.5cm of clear space on each side, which keeps the buttercream off the box walls and leaves room for your fingers when you lift it out. Browse round cake boards and square cake boards in every size from 4 to 20 inches.

Once the board is in, it should fit snugly with only a few millimetres of play on each side. If it can shuffle around, it will, usually at the worst possible moment.

Round cakes in square boxes

Our cake boxes are all square or rectangular, and that's normal. A round board sits perfectly in a square box of the same size, touching all four walls. The empty corners don't matter. The board can't move, and that's what counts.

Inches and centimetres

Australian tins are metric, but cake boxes and boards are still sold in inches. Here's the conversion you'll need.

Remember to convert the board, not the cake. A 20cm cake on a 25cm board is a 10 inch box.

How Tall Should a Cake Box Be?

Width is fixed by the board. Height is where you need to do a little maths.

Measure the finished height of the whole thing: board, cake, piping, and whatever is sitting on top. Then add 2.5 to 5cm. That clearance stops the lid touching your decorations if the box flexes or someone presses on it.

For fragile toppers like acrylic signs, fresh flowers or fondant figures, leave 5 to 7.5cm instead.

Standard boxes are shallow: The classic 4 inch high cake box is about 10cm tall on the inside. A two-layer cake is already around 10cm before you add a single rosette. Those boxes are made for single layers, slices, brownies and cupcakes.

Drum boards add height: A 10mm cake drum adds a full centimetre to your total. Count it.

Tiers add up fast: Each stacked tier, with its board and dowels, adds roughly 9 to 10cm.

Box height guide

Tall Cakes, Tiers and Toppers

Tall cakes are where a standard box gives up. You have a few options, and one of them doesn't involve buying a box at all.

Double barrel and tall cakes

Tall window boxes come in heights of 25cm and 30cm, so you can fit a double barrel cake without squashing the top. Try the 10 inch x 25cm tall window box or the 12 inch x 30cm tall window box.

The 30cm boxes have a base that is separate from the lid. That means you lift the lid off rather than lifting a tall cake up and out over the walls, which is a much calmer experience for everyone.

Tiered cakes

Two tiers can travel stacked, as long as the cake is well chilled and properly supported. Three tiers or more, box each tier separately and stack them when you get there. A pre-stacked cake is heavier, taller and far more likely to tip.

For any stacked cake:

Every tier sits on its own board: The board carries the weight, not the cake beneath it.

Dowel the lower tiers: Place cake dowels towards the outer edge of each tier, not just in the centre. Centre-only support lets the edges sink. A dowel cutter gets them all to the same height.

Add a central dowel for travel: A long dowel pushed through all the tiers and into the base board stops the tiers shifting against each other. Centre hole cake boards make this far easier.

Use a drum for the base: Heavy cakes need a 10mm cake drum underneath, not a thin card board that bends when you lift it.

For heavy stacked cakes, the cake carry box is 14 inches high, heavy duty, and has a handle.

Toppers

The easiest way to fit a tall cake in a smaller box is to take the tall bits off. Acrylic toppers, sugar flowers, fondant figures and candles can all travel separately and go on when you arrive. You save height, and the delicate pieces don't get knocked around on the way.

When it's still too tall

If you're stuck with a box that's a few centimetres short, there's a lid trick. On each side flap of the lid, make two diagonal cuts from the bottom edge towards the top. Tuck the middle section of each flap inside the walls of the box, and the lid sits higher. Tape it down if you're heading outside.

It works in a pinch. A properly sized box works better.

Buttercream, Fondant and Heat

What your cake is covered in changes how you should pack it.

Buttercream

Butter melts at around 32 to 35°C. On an Australian summer day, that's not a high bar.

Chill a buttercream cake until it's firm before it goes anywhere. Firm buttercream holds its shape if the box gets bumped, and the layers underneath won't slide. All-butter buttercream and Swiss meringue buttercream soften fastest in the heat. Buttercream made partly or fully with shortening holds up much better.

Fondant and condensation

Fondant has a different problem. Take a cold cake out of the fridge into a warm, humid room and water beads up all over the surface. The sugar in the icing pulls moisture straight out of the air.

The fix is the box itself. Put the cake in a cardboard box before it goes into the fridge, and leave it boxed for about an hour once it comes out. The condensation forms on the box instead of your cake.

Cardboard works better than an airtight plastic container here, because it lets a little air through. In humid areas like Queensland, a silica gel packet inside the box helps too.

If beads do appear, don't wipe them. Blot gently with paper towel or leave them to evaporate.

Cupcakes

Cupcake boxes use inserts to hold each cake in place. Standard cupcakes need 60mm holes and minis need 40mm, so check the insert before you buy. Tall piped swirls need a taller box, like the 12 cupcake scalloped box at 5 inches high.

How to Keep a Cake Stable in Transit

The right box is half the job. The other half is what happens between your kitchen and the venue.

Here are some handy tips to keep in mind:

Chill it first: Refrigerate the cake overnight, or at least until you're ready to leave. For a tiered wedding cake, 24 hours is better.

Stick it down: A swipe of buttercream or royal icing on the board before you put the cake down stops it sliding off.

Build the box around the cake: With a one-piece box, set the flat base on the bench, place the cake on it, then fold the sides up. No lowering a cake into a box by its edges.

Stop the slide: Put a silicone non-slip mat under the board inside the box, and another under the box in the car. Using a small cake in a big box? Sit a board that fits the box in the bottom, then anchor the small cake's board on top with a non-slip mat or a ring of tape, sticky side out.

Flat surfaces only: The passenger footwell or the boot floor. Car seats slope, and laps move. On hot days, the floor is also the coolest spot in the car.

Cool the car before you load it: Run the air conditioning for 10 to 15 minutes first and keep the box out of direct sun. The RACV has found car interiors can pass 70°C within minutes on a 30°C day. Never leave a cake in a parked car, even for a quick stop.

Drive like you have a cake in the car: Brake early, take corners slowly, and avoid speed bumps where you can.

Carry from underneath: Two hands under the base of the box. Never carry a cake box by the lid.

Slide it out, don't lift it: When you arrive, cut open one side of the box and slide the cake out on its board. It's much safer than lifting a heavy cake up over the walls.

Pack a repair kit: Spare buttercream, a spatula, a piping bag, spare dowels, scissors and paper towel. Something always needs a touch-up.

Cupcakes, Slices and Market Stalls

Cupcake boxes come in singles, fours, sixes, twelves and twenty-fours, with separate mini cupcake boxes in six, twelve and twenty-four. For a school event or a sports club morning tea, a reusable cupcake carrier will outlast a pile of cardboard.

Standard cake boxes also work for cupcakes. A 10 x 10 x 4 inch box holds 12 to 14 standard cupcakes with an insert.

For slices and small cakes at fetes and markets, cake trays are quick and cheap, and cellophane keeps them covered. Selling regularly? Bulk cake boxes come in packs of 25 to 100 and bring the cost per box down considerably.

There are also dedicated cookie boxes and macaron boxes for everything else on the table.

Window Box or Plain Box?

Window boxes let you check the cake without opening the lid, which matters more than it sounds. You can see a problem before you hand it over, and the recipient gets the reveal straight away. They're the obvious choice for gifts and cakes you're selling.

Plain boxes are cheaper, stack easily and come flat packed. For storage, bulk orders, or a cake that's only going from your kitchen to your own table, they do the job perfectly.

Frequently Asked Questions

What size box do I need for an 8 inch cake? A 10 inch box. An 8 inch (20cm) cake usually sits on a 10 inch (25cm) board, and the box has to fit the board. For a standard two-layer cake, choose one at least 6 inches high.

Can I put a round cake in a square box? Yes. A round board fits a square box of the same size, and all our cake boxes are square or rectangular for exactly this reason.

How much bigger than the cake should the box be? Match the width to the board, which should be about 5cm wider than the cake. For height, allow 2.5 to 5cm above the tallest point, or more for delicate toppers.

How do I stop my cake sliding around in the box? Use a box that fits the board snugly, put a non-slip mat underneath the board, and keep the box on a flat surface in the car.

Can I transport a tiered cake already stacked? Two tiers, yes, if the cake is chilled, dowelled and in a tall enough box. Three or more tiers are safer boxed separately and stacked at the venue.

Can I put a cake box in the fridge? Yes, and you should. Boxing a cake before it goes in the fridge protects it from condensation when it comes out. Measure your fridge first, though. A 30cm tall box won't fit on most shelves.

How do I get a cake out of a tall box? Cut down one side of the box and slide the cake out on its board. Or choose a tall box with a separate base, so the lid lifts straight off.

Get the board size right and the height right, and the box stops being a worry. Chill it, stick it down, keep it flat and keep it cool.

Ready to pack up your next bake? Browse the full cake boxes range for standard, window, tall and slab boxes in every size.