Box Size Calculator
Enter your product size and get the right inside and outside box dimensions, the best box style for it, and a free quote in one click.
Your product
1Product size Measure the product, not the box
2Products per box Leave 1 x 1 x 1 for a single item
3How tight should it fit?
4What is the box for?
5Box material Changes the outside size
How to Measure Your Product for a Custom Box
- Measure the product itself, not an old box. Use a ruler or tape and measure at the widest point, including caps, pumps, handles or lids.
- Write down length, width and height. Length and width are the sides you see when you look down into the box, and height is how tall the product stands.
- Add anything that goes in the box with it, such as an insert, tissue paper, a card or a second product.
- Choose how tight the fit should be. The calculator adds a little space so the product slides in without forcing.
Inside vs Outside Box Dimensions
The inside dimensions are the space your product actually gets. The outside dimensions add the thickness of the board on each side. When you order custom boxes, give the inside size and we build the box around it. The outside size matters for shipping cartons, shelves and carrier rates.
| Material | Typical use | Board thickness (approx.) |
|---|---|---|
| Paperboard / cardstock | Retail cartons, tuck end boxes | Very thin, under 1/32 inch |
| E-flute corrugated | Mailer boxes, ecommerce | About 1/16 inch |
| B-flute corrugated | Heavier or fragile products | About 1/8 inch |
| Rigid chipboard | Luxury and gift boxes | About 1/16 to 1/10 inch |
How Much Space Should You Leave?
A box that is too tight is hard to pack and can crush corners. A box that is too big lets the product move and raises your shipping cost, because carriers bill on dimensional weight. As a starting point:
- Snug fit: about 1/8 inch added to each dimension, for retail cartons with no filler.
- Standard fit: about 1/4 inch, for light tissue paper or a thin wrap.
- Extra room: about 1/2 inch, for filler, an insert or padding. For fragile items in bubble wrap, add the wrap thickness on both sides too.
Which Box Style Fits Your Product?
For shipping, mailer boxes in single wall E or B flute handle most ecommerce products up to around ten pounds. Heavier items are safer in shipping boxes or corrugated boxes. Light retail products usually go in tuck end boxes, and premium products in rigid boxes. Still not sure? Compare all box styles.
Frequently Asked Questions
Should I give the inside or the outside size of a box?
Give the inside size. The inside size is what your product needs, and we build the box around it. The outside size depends on the board thickness, which we confirm for you.
How much space should I leave around my product?
For most retail products a snug fit adds about 1/8 inch to each dimension. For mailers with tissue paper, about 1/4 to 1/2 inch is usually enough. Fragile items wrapped in bubble wrap need the wrap thickness on both sides as well.
In what order are box dimensions written?
Box sizes are written as Length x Width x Depth. Length and width are the sides of the opening, with length the longer one, and depth is the height of the box.
Why does box size affect my shipping cost?
Carriers bill on dimensional weight, so an oversized box costs more on every order you ship. A box that fits your product closely keeps that cost down.
Is this calculator exact?
It gives a close starting point. Board thickness and box style change the final size slightly, so our team checks the measurements and confirms the exact specification in your free 3D mockup before anything is printed.
Got your size? Let us build the box.
Free design support, a free 3D mockup, MOQ 100 boxes and free shipping in the USA.