Packaging Size Calculator
Enter your product size, how much padding you want on each side and the board type. The calculator gives the inside and outside box size, the void fill you need, the cardboard in each box and the volumetric weight.
- Box size with padding
- Void fill
- Volumetric weight
Round up to the nearest stock box. A box that is too big costs more to ship and needs more void fill.
Padding goes on every side, so it counts twice in each direction. A 30 × 20 × 15 cm product with 5 cm of padding needs a 40 × 30 × 25 cm box inside. That leaves 21 litres to fill with cushioning. Single-wall board adds about 3 mm a side to the outside.
Padding guide
How much cushioning to use. Search for an item type.
| Product | Padding | Board |
|---|---|---|
| Books and clothes | 1 to 2 cm | Single wall |
| Boxed electronics | 3 to 5 cm | Single or double |
| Glass and ceramics | 5 to 8 cm | Double wall |
| Artwork | 5 cm plus corners | Double wall |
| Heavy machinery parts | 3 to 5 cm | Triple wall |
| Food jars | 3 to 5 cm | Double wall |
Padding on every side.
Padding and box size
A 30 × 20 × 15 cm product. Slide the padding.
The section shows the product in blue, the void fill in yellow and the box wall around it.
How to size packaging
Product to box. Step through it.
Measure the product
Biggest points.
Box makers quote inside sizes. Always compare your inner box size with their listed size.
Single, double or triple wall
Corrugated board. Compare them.
3 mm board.
6 mm board.
10 mm board.
Double wall boxes resist stacking and knocks far better, at about one and a half times the weight.
Before you ship
Packing checks. Tick each item.
Tick each item as you go.
Shake the closed box gently. If anything moves, add more fill.
What you get
Box sizing. Each tile explains one result.
For the product.
For the courier.
Litres.
Per box.
Weight.
Volumetric weight often decides the price for light products, so a smaller box saves money.
Frequently Asked Questions
No question matches that search.
How much bigger should a box be than the product?
Add the padding to every side, so two to ten centimetres more in each direction depending on how fragile it is.
How much padding does a fragile item need?
About five centimetres on every side, with double wall board.
What is void fill?
Any material that fills the empty space, such as paper, air pillows or foam.
Do box sizes use inside or outside measurements?
Box makers usually list inside sizes. Couriers measure the outside.
How thick is cardboard?
Single wall is about three millimetres, double wall six and triple wall ten.
How do I work out volumetric weight?
Multiply the outside length, width and height in centimetres and divide by five thousand.
Why use the smallest box that fits?
It needs less fill, costs less to ship and protects better because the product moves less.
Right size, safe arrival
Size the box to the product plus padding, choose the right board and fill the gaps. Your products arrive safely without paying to ship air.
More size calculators
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