Free technical tool

IVX Box
Calculator

Work out in a few steps which box grade you need — with all outside influences factored in: stacking on the pallet, transport and storage. You can also instantly convert your external dimensions to internal dimensions (or the other way round), so your product always fits precisely and your box is never unnecessarily large or too tight. Fast, free and based on the McKee formula. Applies to the American folding box (FEFCO 0201).

01 — Box & load

Enter the box dimensions, the weight of the contents and whether the product helps bear the stacking load.

02 — Stacking requirement

Specify how high the boxes need to be stacked and under what conditions the pallet will be stored.

03 — Recommendation

The tool automatically selects the lightest flute/grade combination that safely meets the requirement.

Interactive tool

Calculate your flute & grade

Enter your packaging details and stacking requirement. The calculator updates live and shows every combination it considered at the bottom.

What exactly does this tool calculate?

Required strength: how much weight your bottom box has to carry when boxes are stacked on top of it, calculated with the McKee formula — the internationally recognized calculation method for corrugated board.
Realistic board selection: only flute/grade combinations that are actually produced this way — including the practical rule that large boxes need at least double wall corrugated board. Triple wall (BCB) is a specialist grade that is only recommended when double wall genuinely isn't enough, never as a standard option.
Extra safety for real-world conditions: automatic allowances for storage conditions, transport mode and whether the product sits loose in the box — plus a worst-case scenario so you can see the difference.
External ↔ internal dimensions: enter your external dimensions and the tool instantly calculates the usable internal dimensions — or the other way round. That way you choose a box that fits your product precisely, without unnecessary air or too little room.
Fully transparent: at the bottom you can see every combination that was considered, and the disclaimer states exactly which assumptions were made.

SimpleQuick recommendation with smart default assumptions

AdvancedSet transport, storage and product securing yourself

Box & load

Dimension type Are you entering the external dimensions (board size) or the internal dimensions (usable space)?

External dimensions

Internal dimensions

Box dimensions (external, mm)

Derived internal dimensions (indicative)

Length–

Width–

Height–

Calculated as soon as the dimensions are entered.

Weight of the contents per box (kg)

Is the box filled to the top? Does the product touch the lid, or is there space left above it?

No — space above the product

Yes — product touches the lid

Does the product help bear the stacking load? Only possible when the box is full: is the product rigid enough to transfer the pressure itself?

No — the walls bear it alone

Yes — product bears part of the load

Is the product secured in the box? Only relevant when there is space above the product: is it loose, or is it fixed in place (void fill, air cushions, an inlay)? A loose product can shift and knock against the walls during transport, weakening them locally.

No — loose in the box

Yes — fixed/void-filled

In simple mode we calculate conservatively: we assume there is space above the product and that it is not secured. Want to set this yourself? Switch the toggle at the top to "Advanced".

Stacking requirement on the pallet

How many boxes high does this need to stack? Including the bottom box — e.g. 6 layers on a pallet

Transport & storage situation

Storage conditions Transport mode Vibrations, shocks and repeated stacking and unstacking during transport create dynamic loads that a static calculation does not account for.

Recommendation

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Required stacking load–

BCT of recommended combination–

Safe stacking load–

Safety factor breakdown–

Margin vs. requirement–

This recommendation automatically selects the lightest (and therefore most cost-effective) flute/grade combination that meets the stated requirement.

Unlock the full report

Your advice above is free to use. Want to see the worst-case scenario and the full table of every combination considered as well? Enter your name and email address — and we'll gladly think along about your packaging question if you'd like.

Worst-case scenario

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Please note — indicative tool, for FEFCO 0201 only. This calculation assumes an American folding box (RSC, FEFCO 0201) — the McKee formula used here was developed for that style and depends on the perimeter and flute thickness associated with this box code. For other box codes (e.g. FEFCO 0203, 0300, 0409) this recommendation does not give a reliable result. All ECT values are market-indicative, not lab measurements. The transport and securing factors are likewise a technical estimate, not the result of an ISTA/ASTM transport test. The practical limit per box size (single/double/triple wall corrugated board) is based on general industry practice, not on our own production limits; around the 1500–1700 mm perimeter boundary we deliberately show both single and double wall options, because producers differ on this point. For production or customer guarantees we recommend an ECT/BCT test to NEN-EN-ISO standards on the actual material.

Grades to choose from

Standard = the cheapest combination that meets the requirement and is actually produced in this box size. Good and Top provide extra margin for those who prefer to build in some overcapacity. Depending on the box size, these may be two or three different combinations.

Single/double wall transition zone

This box perimeter is close to the practical limit (1500–1700 mm) at which manufacturers switch from single to double wall corrugated board. That is why both types of options are deliberately shown below — if in doubt, ask your supplier which one is actually available in this size.

Level	Flute	Grade	ECT	BCT	Safe load	Margin

Not sure about the recommendation?

This calculator gives you a quick, indicative direction. For technically substantiated advice — including an ECT/BCT test on your actual material — get in touch for personal technical advice.

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