Sizing
Pillow Box Size Guide
A pillow box has three dimensions and only one of them behaves the way you expect. This guide explains what each one does, where the format stops working, and how to specify a size that fits your product rather than approximately containing it.
The three dimensions, and what each controls
Length is the long edge of the flat panel, and it is the only dimension that scales straightforwardly. Make it longer and you get a longer box; the closure is unaffected.
Width is the distance between the two curved end tucks. It is the dimension that determines how much closing tension the box has, because the tuck curve is cut relative to it. A box that is unusually wide relative to its length has less mechanical advantage at the closure.
Depth is the thickness of the finished pack, and it is the one people underestimate most. It is not a free parameter — the curved tuck has to close over that depth, and past a certain point the geometry stops working and the pack springs open.
How the format behaves at different scales
These are not product categories, they are engineering ranges. The specification changes at each step and a box scaled from the wrong band will disappoint.
| Scale | Typical board | What changes |
|---|---|---|
| Under 3 in long | 12pt / 250 gsm | Tuck radius has to widen relative to the box; a heavy board fights the curve |
| 3–5 in long | 12–14pt | Comfortable range; most add-ons available without compromise |
| 5–7 in long | 14–16pt | The general retail default; full artwork becomes readable |
| 7–9 in long | 16–18pt | Bowing starts to appear across the flat face; watch the board |
| Over 9 in long | 18–20pt or E-flute | Needs a wider tuck radius and often an internal support |
Arriving at a size in five steps
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Measure the product at its widest
Its actual widest point, including any cap, lid or label that stands proud — not the nominal figure on a spec sheet.
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Add clearance, not slack
Two to three millimeters on each dimension. A pillow box grips by tension, so a snug fit presents better than a generous one and holds the contents still.
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Establish the depth honestly
Measure the thickest point of the product as it actually sits. This is the dimension the tuck has to close over.
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Check the display
Measure the shelf, hook or counter unit the box has to live in before the dieline is approved, not after.
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Sample it
Ask for a physical sample in the final board and put your own product in it. Thirty seconds with the real thing tells you more than any drawing.
Where sizing goes wrong most often
- Sizing from a nominal product dimension rather than a measured one
- Adding generous clearance, which lets the product rattle and look cheap
- Underestimating depth, which is what makes a pack spring open
- Sizing to the average across a variable product instead of the largest
- Keeping a board weight from a smaller box when scaling up
When to use more than one size
A single box across a product range reduces cost and stockholding, and it works when the range is dimensionally close. It stops working when a box sized for the largest item leaves the smallest rattling around inside it, at which point the saving is being paid for in presentation.
The judgment is usually about depth rather than length — items vary far more in thickness than in footprint. Where you have a genuine split, two sizes normally beats one compromise, and we will show you the cost difference rather than assuming. Our page on the general retail size band covers the format most ranges settle on.
Questions this raises
How small can a pillow box be?
Around two inches across is where the curved tuck starts to become unreliable on a standard board. Smaller is achievable with a lighter stock and a revised tuck radius, and below a certain point a different structure is simply the better answer.
What clearance should I allow around my product?
Two to three millimeters on each dimension is the usual starting point. A pillow box holds by tension, so a snug fit presents better and stops the contents moving.
Why does depth matter so much?
Because the curved end tuck has to close over it. Length and width can grow fairly freely; depth is what determines whether the closure holds at all.
Should I round dimensions to whole numbers?
No. Round to what the product actually needs. A dieline cut to a rounded figure either wastes space or fights the fit, and neither costs less.
Can I reuse a dieline from another supplier?
Usually, if you have the file. Send it with your enquiry and we will tell you whether the tuck geometry and board weight look right for your product, rather than simply copying a specification that may already be the problem.