What is the Carton Size Calculator?
Products are often packed in small inner boxes, which then go into a larger master carton for export or wholesale. The carton size calculator tries every arrangement (rows × columns × layers) for your quantity and suggests the most compact, cube-like carton.
Compact cartons are stronger, cheaper and stack better on pallets. Next, check how many master cartons fit on a pallet with the Pallet Loading Calculator. All calculators accept centimetres, inches or millimetres and kilograms or pounds, so you can use the units on your supplier's spec sheet.
How to use the Carton Size Calculator
- Enter the inner box dimensions.
- Enter the quantity per master carton.
- Add the board thickness.
- Pick from the suggested arrangements.
Formula
Carton inside = (rows × L) × (columns × W) × (layers × H)
Example
24 inner boxes of 10 × 8 × 5 cm can be arranged 3 × 4 × 2 for a carton of about 30 × 32 × 10 cm, or 2 × 3 × 4 for 20 × 24 × 20 cm, which is more cube-like and stronger.
Tips for export cartons
- Keep gross weight under about 20–25 kg for manual handling.
- Avoid very flat or very tall cartons; they crush or tip easily.
- Use dimensions that fit standard pallets (120 × 100 or 120 × 80 cm).
- Print the carton count and weight on the side.
Related packaging and shipping tools
Packaging decisions are connected: the box size sets the volumetric weight, which sets the courier bill, and the carton size decides how many fit on a pallet or in a container. These related calculators help with the next step:
- Container loading calculator: cartons per 20ft or 40ft container.
- Pallet loading calculator: cartons per pallet.
- Pallet capacity calculator: pallets per container.
- Container volume calculator: container sizes and CBM.
- CBM calculator: cubic metres for a shipment.
Frequently asked questions
What is a master carton?
A larger outer box holding several inner boxes or units.
Which arrangement is best?
Usually the one closest to a cube, which uses the least board and stacks well.
Can boxes be rotated?
Yes, the calculator tries different orientations if you allow it.
What is a good maximum carton weight?
Around 20–25 kg for cartons handled by hand.
Does it include board thickness?
Yes, enter it to get outside dimensions.
Is the Carton Size Calculator free to use?
Yes. The Carton Size Calculator on Custom Converter is completely free, with no sign-up, no daily limit and no watermark.
Does the Carton Size Calculator work on mobile phones?
Yes. It is built mobile-first and works on Android phones, iPhones, tablets and computers in any modern browser, with no app to install.