Corrugated Boxes
What Are Corrugated Boxes?
Corrugated boxes are the most widely used shipping container in the world. Unlike simple cardboard (which is a single layer of heavy paper stock), corrugated board consists of a fluted corrugated sheet (the wavy middle layer) sandwiched between two flat linerboard sheets. This three-layer construction gives corrugated boxes their signature strength-to-weight ratio — they're lightweight yet remarkably strong.
The corrugated packaging industry in the United States produces over 31 billion square feet of containerboard annually, serving virtually every industry from e-commerce to food and beverage, electronics, automotive, and agriculture.
Types of Corrugated Board
Single Wall
One fluted sheet between two liners. This is the most common construction for shipping boxes, mailers, and general packaging. Single wall corrugated comes in various flute profiles (A, B, C, E) that determine its thickness, cushioning, and printing characteristics.
Double Wall
Two fluted sheets separated by a liner, with outer liners on each side (5 layers total). Double wall provides significantly greater stacking strength and puncture resistance, making it ideal for heavier products, long-distance shipping, and stacking in warehouse environments.
Triple Wall
Three fluted sheets with four liners (7 layers total). Triple wall corrugated is used as a replacement for wooden crates in heavy-duty industrial applications. It can support loads exceeding 300 lbs and provides exceptional protection for high-value machinery and equipment.
Flute Profiles
| Flute | Thickness | Best For | Characteristics |
|---|---|---|---|
| A-Flute | ~3/16" | Fragile items, cushioning | Excellent cushioning; good stacking strength |
| B-Flute | ~1/8" | Die-cuts, displays, canned goods | Flat surface for printing; good puncture resistance |
| C-Flute | ~5/32" | General shipping (most common) | Good balance of cushioning and stacking strength |
| E-Flute | ~1/16" | Retail packaging, mailers | Thin profile; excellent print surface; lightweight |
| F-Flute | ~1/32" | Small retail boxes, fast food | Ultra-thin; replaces folding cartons |
C-flute is the default for most standard shipping applications. If you're unsure which flute to specify, start with C-flute in 32 ECT for items under 40 lbs and 44 ECT for heavier items.
Common Box Styles
RSC (Regular Slotted Container) — The most common and cost-effective box style. All flaps are the same length, and the outer flaps meet at the center. Used for the majority of shipping applications.
FOL (Full Overlap) — Similar to RSC but with full-length outer flaps that completely overlap, providing extra stacking strength and top/bottom protection. Preferred for heavy items.
HSC (Half Slotted Container) — An RSC with flaps on only one end, creating an open-top box. Used as trays, bins, or with a separate lid.
Die-Cut — Custom-shaped boxes cut from flat corrugated sheets using a steel rule die. Allows complex shapes, self-locking tabs, windows, and unique designs.
Standard Box Sizes
While corrugated boxes can be made to virtually any dimension, stock (standard) sizes are the most cost-effective because they require no custom tooling. Common stock sizes include:
| Size (L × W × H) | Common Use |
|---|---|
| 6 × 6 × 6" | Small items, mugs, candles |
| 10 × 8 × 6" | Books, small electronics |
| 12 × 12 × 12" | Medium items, multiple small products |
| 18 × 14 × 12" | Clothing, housewares, medium products |
| 24 × 18 × 18" | Large items, bulk shipments |
| 24 × 24 × 24" | Large/heavy items, multi-piece orders |
Need Corrugated Boxes? Get Matched with Suppliers
Tell us your specifications and we'll connect you with verified corrugated box manufacturers.
Get Free Quotes →How to Choose a Corrugated Box Supplier
When evaluating corrugated box manufacturers, consider these factors: minimum order quantities (which range from 100 to 10,000+ units depending on the supplier), geographic proximity (which affects freight costs and lead times), available flute types and board grades, printing and customization capabilities, sustainability certifications (FSC, SFI), and quality testing standards (ECT ratings, ISTA certification).
For a complete evaluation framework, read our guide on how to choose a corrugated box supplier.