Corrugated Box ECT Ratings: 32 ECT vs 44 ECT Explained (2026)
What Is ECT Rating on Corrugated Boxes?
ECT (Edge Crush Test) measures the amount of force a corrugated board can withstand when compressed on its edge before it crushes. It is the industry-standard metric for determining how much weight a corrugated box can support — particularly important for products that will be stacked on pallets in warehouses.
Quick answer: 32 ECT (the standard) supports up to 65 lbs and is suitable for most e-commerce and retail shipping. 44 ECT supports up to 95 lbs and is required for heavy-duty industrial applications and tall pallet stacks.
ECT Rating Chart
| ECT Rating | Weight Capacity | Wall Type | Thickness | Best For | Cost Impact |
|---|---|---|---|---|---|
| 23 ECT | Up to 35 lbs | Single Wall | ~2.5mm | Very light items, internal packaging | -15% below baseline |
| 32 ECT | Up to 65 lbs | Single Wall | ~3.2mm | Standard shipping, e-commerce (most common) | Baseline |
| 40 ECT | Up to 80 lbs | Single Wall | ~3.5mm | Moderately heavy items | +15% |
| 44 ECT | Up to 95 lbs | Single Wall | ~3.8mm | Heavy items, pallet stacking | +20–25% |
| 48 ECT | Up to 120 lbs | Double Wall | ~6.0mm | Very heavy items, fragile goods | +35–45% |
| 51 ECT | Up to 140 lbs | Double Wall | ~7.0mm | Industrial equipment, machinery | +50–60% |
| 61 ECT | Up to 180 lbs | Triple Wall | ~12mm | Crated goods, export shipping | +80–100% |
32 ECT vs 44 ECT: When to Upgrade
The most common decision brands face is whether to use standard 32 ECT or upgrade to 44 ECT. Here's when each makes sense:
Choose 32 ECT When:
- Product weight is under 50 lbs (including packaging)
- Boxes are stacked no more than 3–4 high on pallets
- Shipping via parcel carriers (UPS, FedEx, USPS)
- Products are not fragile or moisture-sensitive
- Cost optimization is a priority
Choose 44 ECT When:
- Product weight exceeds 50 lbs
- Boxes are stacked 5+ high in warehouse environments
- Shipping via LTL freight with rough handling
- Products are heavy and fragile (appliances, large electronics)
- Warehouse humidity or temperature variations are a concern
ECT vs Mullen Burst Test
Two standards are used to rate corrugated board strength:
| Test | What It Measures | Best For | Industry Trend |
|---|---|---|---|
| ECT (Edge Crush Test) | Stacking strength — resistance to vertical compression | Warehouse stacking, pallet shipping | ✅ Modern standard |
| Mullen (Burst Test) | Puncture resistance — force needed to burst through the board | Rough handling, puncture risk | ⚠️ Legacy standard |
Industry shift: ECT has largely replaced Mullen as the primary strength rating because modern supply chains rely more on pallet stacking than individual package handling. If your boxes are palletized, ECT is the relevant metric.
How ECT Affects Your Box Cost
For a standard 12×10×6" RSC box at 2,500 units:
| ECT Rating | Cost Per Unit | Annual Cost (10,000 boxes) | Savings vs 44 ECT |
|---|---|---|---|
| 32 ECT | $1.20 | $12,000 | 20% savings |
| 44 ECT | $1.50 | $15,000 | Baseline |
| 48 ECT (DW) | $1.90 | $19,000 | -27% more |
Cost optimization tip: Many brands default to 44 ECT "just to be safe," but 80% of e-commerce products ship safely in 32 ECT. Switching from 44 ECT to 32 ECT saves 20% per unit — at 10,000 boxes/year, that's $3,000 in annual savings on box costs alone.
Frequently Asked Questions
Can 32 ECT boxes be stacked on pallets?
Yes, but with limits. 32 ECT single-wall boxes can typically handle 3–4 layers of stacking. For tall pallet stacks (5+ layers), upgrade to 44 ECT or double-wall construction.
Does higher ECT mean thicker boxes?
Generally yes, but not always. ECT can be increased by using a higher-grade linerboard without changing flute type or thickness. However, moving to double-wall construction significantly increases both ECT and physical thickness.
What ECT rating does Amazon require?
Amazon's FBA requirements specify a minimum of 32 ECT for standard shipments and 44 ECT for items over 60 lbs. All boxes must pass a 6-foot drop test without damage to the contents.
Need help choosing the right ECT rating? Get a free quote for your custom corrugated boxes or ask our AI consultant for a recommendation based on your product weight and shipping method.