Free tool
Box size calculator
Enter your product size and see the right box in 3D — inside and outside size for 12 box styles and the stocks we print on, multi-pack layouts, shipping weight for UPS, FedEx and USPS, a dieline guide and pallet counts. Free, no sign-up.
Enter your product size — the box, its inside and outside size, shipping weight, dieline and pallet count appear here.
Other layouts
| Layout | Inside | Outside vol. | DIM |
|---|
| Carrier and rate | DIM weight | Billable |
|---|
Add the packed weight for billable weight — carriers bill the higher of the two.
Carrier size limits
Ways to save
The same product in every style (typical board for each). Pick one to switch.
| Style | Outside ≈ | DIM | Board |
|---|
Outside sizes are estimates from typical board thickness; your dieline fixes the exact size — our design team sets it up free with a digital proof.
Using the calculator
- Measure the product at its widest points. How to measure.
- Choose the protection: snug for retail cartons, wrapped for tissue, fragile for breakables in loose fill.
- Pick a style and board. Not sure? See box styles explained and flute types.
- Get a quote with the inside size filled in — no minimum order, free dieline and digital proof.
How the calculations work
| Result | Formula |
|---|---|
| Inside size | product (or product layout) + 2 × clearance + 2 × insert wall, on each dimension; rounded up to the next 1/16 in or mm to order |
| Outside size (t = board) | mailer +4t L, +2t W and H (folded double ends) · tuck end and tuck top +2t L and W, +4t H (closures) · auto bottom +5t H · shipping carton +2t L and W, +4t H (double flaps) · two-piece carton +4t + 1 mm L and W, +2t H · sleeve and tray +2t L, +4t + 1 mm W, +3t + 1 mm H · gable adds the roof (≈ ½ W) and a 35 mm handle · rigid lid and base +4t + 2 mm L and W, +2t H · magnetic flap +2t + 3 mm L, +4t + 2 mm W, +3t + 1 mm H · rigid drawer +2t L, +4t + 2 mm W, +3t + 2 mm H |
| Volume and girth | L × W × H (1 in³ = 16.387 cm³); girth = 2 × (the two shorter outside sides) |
| Dimensional weight | each outside side rounded up to a whole inch; L × W × H ÷ divisor, rounded up to a whole pound (139 UPS/FedEx daily, 166 UPS retail, 139 USPS above 1,728 in³) · metric: cm³ ÷ 5,000 or 6,000, rounded up to 0.5 kg |
| Billable weight | the higher of actual weight and dimensional weight |
| Dieline guide and board | flat layout of the panels, closures and glue flap for the style (inside size + board), area summed for board per box |
| Pallet pack-out | boxes per layer (best of both orientations) × whole layers under your load height · US pallet 48 × 40 in, EUR pallet 1200 × 800 mm |
| Space used | product volume ÷ inside volume |
Stocks and thicknesses match what we offer: cardstock, kraft, bux board, texture card and cardboard in points (1 pt = 0.001 in), corrugated F, E, B, C, A, EB and BC flutes, and rigid greyboard 1.5–3 mm. You can type the exact thickness if you know it. Carrier rules are the published rules we checked in September 2026 — carriers update them, so confirm with yours before relying on a result for billing.
Guides that help
- How to measure box dimensions the right way
- Box styles explained
- Corrugated flute types
- What is a dieline?
- Rigid box vs folding carton
Frequently asked questions
How does the box size calculator work?
It adds your chosen clearance to the product size to get the inside dimensions, then adds the board walls for the box style you pick to estimate the outside dimensions. From the outside size it works out volume, dimensional weight and carrier limits.
Are the outside dimensions exact?
They are close estimates based on typical board thicknesses and how each style folds. The exact outside size is fixed by the dieline for your box, which our design team prepares for free when you order.
What clearance should I use?
Snug (about 1 mm a side) for retail cartons, wrapped (about 3 mm) for items in tissue or a sleeve, padded (about 12 mm) for light cushioning and fragile (50 mm, the two inches UPS recommends) for breakable items in loose fill. You can also type your own.
Which dimensional weight divisor should I use?
Use 139 for UPS and FedEx daily (account) rates, 166 for UPS retail rates and 139 for USPS Ground Advantage parcels over one cubic foot. For international express in metric, 5,000 cm³ per kg is common; some services use 6,000.
Can it size a box for several items?
Yes. Enter how many items go in the box and it tries every layout (for example 6 × 1 × 1, 3 × 2 × 1, 2 × 3 × 1) and every allowed orientation, then ranks them by box volume or dimensional weight.
Can I see the box in 3D?
Yes. The preview is drawn to your exact proportions for the style you pick. Drag it to turn it, open and close the lid, show the product inside, and change the print colour, lamination, foil, spot UV, embossing, window and ribbon to see the effect. Use Full screen for a bigger view; press Esc or the close button to return.
Does it make a dieline?
For folding cartons, mailers, shipping cartons, two-piece and sleeve boxes it draws a dieline guide with cut and fold lines that you can download as an SVG, plus the board area per box. It is a guide only: our design team prepares the production dieline for your exact box free when you order.
How many boxes fit on a pallet?
Open the Pack-out tab. It works out boxes per layer on a US (48 × 40 in) or EUR (1200 × 800 mm) pallet, the number of layers under your load height and the total, or how many boxes fit in your own shipping carton.
Does it store my measurements?
No. Everything is calculated in your browser. The share link simply puts your inputs in the web address so you can send or bookmark it.