Packaging tools
Box size finder
Enter your item's dimensions and how much protection it needs. This tool adds padding on every side, then snaps the result up to the nearest real stock box size — so it never recommends a size that isn't made. Flat, low-profile items get routed to a mailer instead.
Recommended box
How to size a box
Start from the item, not the box. Measure length, width, and height, then decide how much cushioning the contents need — roughly a quarter inch for a snug non-fragile fit, about an inch for typical goods, two inches or more for fragile items. Add that padding to each pair of faces to get the interior you need, then round each side up to the nearest real stock size. A box only slightly larger than the item keeps void fill low and helps you stay under the next dimensional-weight threshold.
Common questions
How much space should I leave around my item?
A common rule is roughly 1 inch of cushioning on every side for typical goods and 2 inches or more for fragile items. Tightly fitted, non-fragile products can use about a quarter inch. This tool applies your chosen padding to all four sides and to the top and bottom, since a flat item often needs less lid clearance than side padding.
Why does the interior size add padding on both sides?
Padding sits on each face of the item, so each dimension grows by twice the padding on that pair of faces. A 6-inch-wide item with 1 inch on each side needs an 8-inch-wide interior. Length and width use the side padding; height uses the top-and-bottom padding.
Why snap to a standard box size?
Stock boxes come in fixed sizes. This tool rounds each dimension up to the next real stock size (such as 4, 6, 8, 9, 10, 11, 12, 14, 16, 18, 20, or 24 inches) so the box it recommends is one you can actually buy. You then fill the small remaining gap with void fill.
How does box size affect shipping cost?
Carriers bill the greater of actual and dimensional weight, and dimensional weight rises with volume. A box only slightly larger than needed keeps you under the next billable pound, so right-sizing the carton reduces what you pay to ship.
When should I use a mailer box instead?
For flat, lightweight, or lower-profile items, a mailer box can protect the product with less volume and less void fill than a standard cube-shaped box. When your padded item comes out flat, this tool routes you to the mailer option first.