FREE ENGINEERING TOOL · McKEE FORMULA

Box compression
strength calculator.

Estimate BCT from board grade and box dimensions, derate for real warehouse conditions, and check whether your pallet stack holds. The same first-pass math our engineers run on every spec.

Predicted BCT

McKee estimate of peak compression strength, as-manufactured, lab conditions.

Derated working strength

After environment factors and safety factor — the number you can actually stack against.

Max safe boxes per column

At the loaded box weight you entered, bottom box governs.

Your stack

SHOW THE MATH

No black box.

Enter a spec above — the full calculation appears here.
FactorConditionMultiplier
Storage timeCross-dock (<1 day)1.00
10 / 30 / 90 / 180+ days0.65 / 0.60 / 0.55 / 0.50
Humidity50 → 90% RH1.00 → 0.52
Stacking patternInterlocked vs column0.55 vs 1.00
Pallet overhangAny edge overhang0.68

Method: simplified McKee formula, BCT = 5.87 × ECT × √(caliper × perimeter), with derating multipliers in the ranges published by the Fibre Box Handbook and TAPPI. This is a first-pass engineering estimate — it assumes standard RSC construction and does not replace physical compression testing (TAPPI T804) or ISTA transit validation. For a spec you can put a PO against, send it through and a Rox engineer will verify board grade, run samples, and quote it firm.

NEXT STEP

Get this spec verified & quoted.

Send the same dimensions and board grade through our RFQ — firm price and lead time back within 24–48 hours, reviewed by a real packaging engineer.

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