Understanding Corrugated Box Strength: Burst & Edge Crush Explained

Two boxes can look identical yet perform completely differently. The difference is in the board’s strength rating — and knowing how to read it helps you buy boxes that actually protect your goods. Here’s a plain-English guide.

Why Strength Ratings Exist

A box has to resist two main forces: pressure on its surface (a poke or drop) and weight stacked on top (in a warehouse or truck). Two tests measure these.

Burst Strength (Bursting Test)

• Measures how much pressure the board takes before it punctures.
• Often shown in kg/cm² or as a “bursting factor”.
• Good indicator of resistance to rough handling and drops.

Edge Crush Test (ECT)

• Measures how much stacking pressure the box edges can bear.
• Higher ECT = better stacking strength.
• Important if boxes are stored or transported stacked.

Which Matters for You?

• Shipping single parcels, rough handling → focus on burst strength.
• Warehousing / stacking / palletising → focus on ECT.

GSM Is Not the Whole Story

A higher paper GSM often means a stronger box, but flute type and construction matter just as much. Don’t judge strength by thickness alone — check the actual rating where you can.

Match Strength to Contents

• Light goods: standard single-wall ratings are fine.
• Heavy/fragile: ask for higher burst and ECT values.
• Export/long transit: specify tested, certified board.

A Practical Tip

If you ship in volume, ask your supplier for the box’s burst/ECT specs and test a sample loaded to your real weight. It’s the surest way to avoid in-transit failures.

Find quality-rated corrugated shipping boxes at Sotiracollective — free delivery across India, with 7-day returns.