Bakery boxes with windows: sizes, grease resistance and food-contact facts
A bakery box with a window is a lock-corner folding carton on 18pt food-contact grade SBS with a die-cut opening covered by clear PET film, or left open; whole cakes step up to 20pt board. Grease resistance comes from a coating or a liner, not thickness. Common sizes are 10 by 10 by 5 inches for a cake and 8 by 5.5 by 2.5 for cookies.
What the board does and does not do
Bakery boxes run on solid bleached sulfate board, SBS, because it is clean, white on both sides on the food-contact grades, and holds a crease well after being folded flat and popped open a few hundred times a day. 18pt handles cookies, macarons, cupcakes and pastries; it is what our bakery box with a window is made from. Our cake box moves to 20pt, because a cake over about 3 pounds or taller than 5 inches needs stiffer walls.
The inside surface is what matters for food. A food-contact grade SBS has a clay coat on the print side and a clean uncoated or lightly coated inside. Standard packaging SBS is not always a food-contact grade, so it should not be used for anything the food touches. Food-contact documentation for the board is available on request and supplied with the quote. Where the product is dry and wrapped, a cookie in a cellophane sleeve for instance, the box is secondary packaging and the rule relaxes.
Grease resistance, honestly
Board does not resist grease on its own. A croissant left on bare SBS for an hour leaves a mark, and butter through the base of a cake box is a standard complaint. There are two fixes. A grease-resistant coating applied to the inside of the sheet before it is cut, which is the cleanest option and is standard on our bakery box with a window. Or a greaseproof paper liner or cake board dropped in at the bench, which is cheap and the most common fix. Our glassine guide covers when a liner is worth it.
For a cake box we suggest the coating on the base panel and a cake board. For a pastry box that holds product for a couple of hours, a liner does the job. For a doughnut box, the coating, because sugar and oil together go through anything. Whichever route you take, test it with the real product on a warm afternoon before ordering the run.
Common bakery box sizes
| Use | Inside size (in) | Board | Window | Structure |
|---|---|---|---|---|
| Cookies, 6 to 12 | 8 x 5.5 x 2.5 | 18pt | Top, 6 x 3.5 | Tuck top, auto-lock bottom |
| Macarons, 6 or 12 | 8.5 x 3 x 2 or 8.5 x 5 x 2 | 18pt with insert | Top, full length | Sleeve and tray or tuck top; see the macaron box |
| Cupcakes, 6 | 10 x 7 x 4 | 18pt with 18pt insert | Top, 8 x 5 | Tuck top, lock bottom |
| Cake, 8 inch | 10 x 10 x 5 | 20pt | Top, 7 x 7 | One-piece lock corner |
| Cake, 6 inch tall | 8 x 8 x 6 | 20pt | Top and one side | One-piece lock corner |
| Pastries, 4 to 6 | 9 x 6 x 3 | 18pt | None or top | Tuck top, auto-lock bottom |
The window: film, no film, or a die-cut pattern
A window is a die-cut hole with a clear film glued to the inside of the board. The film we use is PET at about 3 mil, which is clear, stiff and does not fog from a warm product as fast as thinner films. It is food-contact grade, with documentation supplied with the quote. Plant-based PLA film exists, but it fogs more and creases when the box is folded flat, so it is not part of our standard range. Keep the window at least half an inch from any fold, and at least three quarters of an inch from the lock tabs, or the board weakens where it is handled.
A window with no film is the honest answer for a box that will be sold across a counter and eaten within the hour. It keeps the box recyclable as paper and lets the product breathe, which stops a warm croissant steaming itself soft. It does not suit anything that will sit in a display case for a day. For that, the film.
An illustrative spec: a six-cookie gift box
Illustrative spec, not a client order.
Say a bakery wants a boxed set of six large cookies for gifting and local delivery, 500 boxes. The build we would suggest is an 8 by 5.5 by 2.5 inch tuck top carton with an auto-lock bottom on 18pt food-contact grade SBS, a 6 by 3.5 inch top window with 3 mil PET film, and a grease-resistant coating on the inside of the base panel. Full color print outside, matte aqueous coating, and the logo in one color on the inside of the lid so it shows through the window when the box is closed.
The cookies sit two by three on a glassine sheet. The box ships flat and the auto-lock bottom pops open in one motion, which matters at a busy counter. Expect 10 to 12 business days after proof approval, the lead time on the bakery box with window page. The window film is the only part that is not paper, so the base is a good place to say so.
What has to be on a bakery box
For a box sold at the counter and eaten fresh, very little, since the counter label carries the information. For anything sold packaged at retail, the FDA food labeling rules in 21 CFR Part 101 require the product name, net quantity, ingredient list, allergen information and the name and place of business. Many bakeries put these on a sticker so the printed box stays clean and the batch details can change. We leave a 3 by 2 inch clear area on the base or the back panel for it. This is packaging guidance, not legal advice. A bakery selling into retail should also check its state and local rules, which can add to the federal ones.
Questions people ask
Can the box go in a fridge or a freezer?
A fridge, yes, for a day or two. SBS softens as it takes on moisture and the window film may fog. A freezer, no, unless the product is wrapped inside; the board goes limp on thawing and the glue on the window can release. For frozen product, a freezer-grade frozen food bag is the better package.
Is a kraft bakery box a good idea?
It looks right for a rustic brand and prints well in one color. The catch is grease: natural kraft shows every mark and there is no clay coat. Use a food-contact kraft grade with a grease-resistant coating, or line it, and keep the window on the lid rather than the side.
What is the difference between a lock corner cake box and a tuck top?
A lock corner box is one piece that folds up with tabs locking at each corner, so the lid hinges from the back and the whole thing opens wide, which is how you get a cake out. A tuck top with an auto-lock bottom closes with a tuck flap and suits cookies and cupcakes lifted out from above.
Bakery box or cake box: which guide do I need?
This guide covers windowed bakery boxes for pastries, cookies, cupcakes and macarons, including grease resistance and window film. For whole cakes, the cake box sizing guide goes deeper on matching the box to the cake board, depth for tall cakes and front-loading lids.