Use case · Strength
Box compression strength (BCT, from the Box Compression Test) is the vertical load an empty carton withstands before it buckles. Without a lab, you can estimate it with the McKee formula from edge crush test (ECT), board thickness and carton perimeter. JetPallet works out this estimate for your carton, divides it by your safety factor and compares the result with the load resting on the bottom carton of the planned pallet.
Column and interlocked stacking
Workflow
Enter carton, weight and pallet. JetPallet calculates the pattern and the number of layers. The load on the bottom carton follows from the full layers above it.
Open “Compression strength …” and enter ECT and board thickness – or pick flute type and grade from the small catalogue. If you have a measured BCT, enter it; it then takes precedence over the estimate.
The overall safety factor covers storage time, humidity, stacking pattern and overhang. You set it yourself; JetPallet does not supply a default.
The verdict is “permitted” or “too high”, each with the headroom as a percentage. The headroom also appears in the inspector next to the pallet and updates as soon as you change layers, weight or carton size.
A taller pallet saves floor space and trips. But every extra layer presses down on the cartons beneath it. Whether the bottom carton survives weeks in storage, humidity and the chosen stacking pattern often only becomes clear when it gives way.
Lab BCT values are not always available, especially for new carton sizes. A transparent estimate helps you sort options early: which height is plausible, where there is headroom, and where you should ask for a stronger board grade or a proper measurement.
What you end up with
In detail
01
JetPallet uses the simplified McKee formula: BCT = 5.874 · ECT · √(t · Z), with ECT in kN/m and board thickness t and carton perimeter Z in mm. Example: an ECT of 7 kN/m, 4 mm board and a 1,200 mm perimeter (roughly a carton with a 400 × 200 mm footprint) give about 2,849 N.
02
The permissible load is the BCT divided by your safety factor. It is compared with the static load of all full layers above the bottom carton – taken from the planned pallet, not from a rule of thumb. If inputs are missing, the result reads “incomplete”, never “permitted”.
03
For single-wall (B, C, E) and double-wall board (BC, EB), the catalogue holds the minimum ECT per grade and thickness ranges from documented sources. Picking an entry fills in the minimum ECT and the lower thickness, so the check errs on the safe side. JetPallet also shows a range from minimum, typical and maximum thickness. Supplier data and measured values take precedence.
Questions
BCT stands for Box Compression Test: the vertical load at which an empty carton buckles in a test press. For pallet planning it is divided by a safety factor, because storage time, humidity and stacking pattern reduce the load a carton can carry.
It is an approximation based on edge crush, board thickness and carton perimeter. It is useful for a first comparison of options but does not replace a measurement, which is why a measured BCT takes precedence in JetPallet.
That depends on storage time, climate, stacking pattern and overhang, and is best agreed with your packaging supplier. JetPallet deliberately does not set a default.
Read on
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