TestingStandard

ECT vs BCT — which one matters?

ECT measures the board; BCT measures the finished box. Use ECT for material specs, BCT for stacking predictions.

Testing Standards

8 minadvanced·Updated 2026-06-25

Overview

Buyers increasingly specify ECT instead of burst because it correlates more directly with real-world stacking. BCT remains the acceptance test for palletized shipments — it is what a stack of boxes will actually survive.

Specifications

ECT unit	kN/m or lb/in
BCT unit	N or kgf
Standard	TAPPI T839 / ISO 3037

Common mistakes

Comparing ECT boards of different flute profiles as equal
Ignoring humidity — BCT can drop 50% at 90% RH

AI Summary

ECT (Edge Crush Test) predicts stacking strength from the corrugated board itself. BCT (Box Compression Test) tests the whole assembled box. McKee formula links them: BCT ≈ 5.87 × ECT × √(thickness × perimeter).