The Complete Guide to Corrugated Box Selection
Everything you need to know about choosing the right corrugated box for any application — from box styles and wall construction to flute profiles, strength ratings, and cost optimization.
In This Guide
Box Styles Explained
Corrugated boxes come in a wide range of styles, each engineered for specific applications. Understanding the differences between these styles is the first step toward making smarter packaging decisions. The style you choose affects everything from product protection to packing speed to shipping costs.
RSC — Regular Slotted Container
The RSC is the most common box style in the world, accounting for roughly 80% of all corrugated boxes produced. All four flaps on both the top and bottom are the same length, and the outer flaps meet at the center when folded. RSC boxes are manufactured from a single piece of corrugated board, making them extremely cost-effective. They ship flat, assemble quickly, and are available in virtually any size.
Best for: General shipping, storage, e-commerce fulfillment, retail distribution. If you're unsure which style to choose, the RSC is almost always a safe starting point.
HSC — Half Slotted Container
An HSC is essentially an RSC with only one set of flaps — either the top or the bottom is open. This design is ideal when items are loaded from the top and the box remains on a pallet or shelf. HSCs are commonly used in retail display applications where the open top allows easy access to the product inside.
Best for: Retail displays, produce packaging, tray-style applications, items that need to be accessed frequently without fully opening the container.
FOL — Full Overlap Container
In a FOL box, all flaps are the same length and extend the full width of the box so they completely overlap when closed. This double layer of corrugated board on the top and bottom provides significantly more stacking strength and puncture resistance than a standard RSC. FOL boxes use more material, so they cost more, but the added protection is often worth the investment.
Best for: Heavy items, long-distance shipping, applications requiring extra stacking strength or bottom support, items that need protection from rough handling.
Telescope Boxes
Telescope boxes consist of two separate pieces — a top (lid) and a bottom (base) — that slide over each other. The design creates a clean, finished appearance and allows the box depth to be adjusted by varying how far the lid slides down. Full telescope designs have a lid that extends all the way to the base, while partial telescope designs have a shorter lid.
Best for: Flat items like artwork and mirrors, items of variable height, premium presentation packaging, and products that require a polished unboxing experience.
Die-Cut Boxes
Die-cut boxes are manufactured using a custom die (a sharp steel cutting tool) that cuts and scores the corrugated board into virtually any shape. This process allows for unique designs including built-in handles, interlocking tabs, display features, and custom inserts — all from a single piece of board. While tooling costs are higher upfront, die-cut boxes eliminate the need for separate inserts or accessories.
Best for: Retail packaging, subscription boxes, products requiring custom inserts, mailer boxes, and any application where presentation and brand experience matter.
Wall Construction
The "wall" of a corrugated box refers to the layered construction of the board itself. Every corrugated panel consists of flat linerboard sheets bonded to a wavy, fluted medium. The number of these layers determines the wall type and, ultimately, the strength and performance of the box. Choosing the right wall construction is one of the most important decisions in box selection.
Single Wall
Single wall corrugated consists of one fluted medium sandwiched between two flat linerboard sheets. This is the most common and economical wall type, suitable for the vast majority of shipping and storage applications. Single wall boxes typically handle products weighing up to 40–50 lbs depending on the flute profile and board grade used.
Thickness: Approximately 1/8" to 3/16" depending on flute type. Single wall is the go-to choice for everyday shipping, e-commerce, and light industrial applications.
Double Wall
Double wall corrugated features two fluted mediums separated by a flat linerboard sheet, with linerboard on the outside as well. This five-layer construction provides roughly twice the stacking strength and puncture resistance of single wall. Double wall is the standard for gaylord boxes, heavy-duty shipping containers, and boxes that need to support significant stacking loads.
Thickness: Approximately 1/4" to 5/16". Often uses a combination of flute profiles (such as BC-flute) to balance cushioning with stacking strength.
Triple Wall
Triple wall corrugated contains three fluted mediums and four linerboard sheets for a total of seven layers. This construction creates an exceptionally rigid, durable container that can support loads exceeding 2,000 lbs. Triple wall boxes are often used as an alternative to wooden crates for heavy industrial shipments, automotive parts, and machinery.
Thickness: Approximately 3/8" to 1/2". Triple wall is significantly heavier and more expensive than double wall, but it offers wood-crate-level protection at a fraction of the weight.
Flute Profiles
The fluted medium inside a corrugated wall is what gives the box its cushioning and rigidity. Flutes come in different sizes, designated by letter. The flute size affects cushioning, stacking strength, printability, and the overall thickness of the board. Choosing the right flute profile is essential for matching box performance to your specific needs.
Here is a detailed breakdown of the five most common flute profiles used in corrugated packaging today:
| Flute | Height | Flutes/ft | Key Characteristics |
|---|---|---|---|
| A-Flute | 1/4" (6.4mm) | 33-36 | Best cushioning, highest stacking strength, thickest profile |
| B-Flute | 1/8" (3.2mm) | 47-52 | Excellent flat crush resistance, great printability, compact |
| C-Flute | 11/64" (4.4mm) | 39-43 | Best all-around compromise of cushioning, strength, and cost |
| E-Flute | 1/16" (1.6mm) | 90-98 | Superior print surface, thin profile, ideal for retail |
| F-Flute | 1/32" (0.8mm) | 125+ | Ultra-thin, near-folding-carton quality, premium printing |
A-Flute (1/4")
A-Flute was the original corrugated flute and remains the thickest standard profile. With approximately 33 flutes per linear foot, it provides the greatest cushioning and highest stacking strength of any single-wall construction. A-Flute is ideal for fragile items that need maximum protection during transit. The tradeoff is a rougher print surface and greater material usage. A-Flute is commonly used for glass products, electronics, and items that require superior shock absorption.
B-Flute (1/8")
B-Flute has a shorter, denser flute structure with about 47–52 flutes per foot. This gives it excellent flat crush resistance, meaning it holds up well under pressure from above. The smaller flute size also provides a smoother surface for printing, making it popular for die-cut retail packaging and point-of-purchase displays. B-Flute is a workhorse for canned goods, beverage cartons, and inner packaging.
C-Flute (11/64")
C-Flute sits between A and B in terms of thickness and is by far the most widely used flute profile in North America. It offers an excellent balance of cushioning, stacking strength, and cost efficiency. Most standard RSC shipping boxes use C-Flute construction. If you ship a mix of products and need one versatile box type, C-Flute is the default choice. It accounts for roughly 80% of all corrugated production.
E-Flute (1/16")
E-Flute is a micro-flute profile that provides an exceptionally smooth printing surface while still offering corrugated-level protection. With about 90–98 flutes per foot, the thin profile reduces storage space requirements and material costs. E-Flute is commonly used for premium retail packaging, cosmetics, pizza boxes, and mailer boxes where brand presentation is important but structural strength is still needed.
F-Flute (1/32")
F-Flute is the thinnest standard flute profile, approaching the thickness of a folding carton while retaining the structural advantages of corrugated construction. With 125+ flutes per foot, it delivers near-litho print quality. F-Flute is used in high-end retail packaging, jewelry boxes, and applications where shelf appearance is paramount. It is also increasingly popular for fast-food clamshell containers and specialty food packaging.
Strength Ratings: ECT & Mullen
Two standardized tests are used to measure corrugated box strength: Edge Crush Test (ECT) and Mullen Burst Test. Understanding both is critical for selecting a box that can handle your shipping and stacking requirements without over-engineering (and overpaying).
Edge Crush Test (ECT)
ECT measures the amount of force per unit length (lbs per linear inch) that a corrugated board sample can withstand before crushing when the force is applied to its edge. This test directly correlates to a box's stacking strength — its ability to support weight when boxes are stacked on pallets. ECT has become the preferred rating method in the corrugated industry because it more accurately predicts real-world performance for palletized shipments.
| ECT Rating | Wall Type | Max Content Weight | Common Use |
|---|---|---|---|
| 23 ECT | Single Wall | Up to 20 lbs | Lightweight goods, apparel |
| 29 ECT | Single Wall | Up to 40 lbs | Standard shipping |
| 32 ECT | Single Wall | Up to 65 lbs | Most common rating |
| 40 ECT | Single Wall | Up to 80 lbs | Heavy single-wall |
| 42 ECT | Double Wall | Up to 80 lbs | Double wall standard |
| 48 ECT | Double Wall | Up to 100 lbs | Heavy-duty shipping |
| 51 ECT | Double Wall | Up to 120 lbs | Industrial, export |
| 61 ECT | Double Wall | Up to 140 lbs | Very heavy items |
| 71 ECT | Triple Wall | Up to 180 lbs | Machinery, auto parts |
| 82 ECT | Triple Wall | Up to 240 lbs | Wood crate replacement |
Mullen Burst Test
The Mullen test measures the pressure (in pounds per square inch) required to burst through the face of a corrugated board sample. This test is most relevant when the primary concern is puncture resistance rather than stacking strength — for example, when boxes are not palletized and may be handled individually, or when sharp or heavy contents could puncture the box wall from the inside.
Common Mullen ratings include 125#, 150#, 175#, 200#, and 275# for single wall, and 350#, 400#, 500#, and 600# for double wall. The higher the number, the more force required to puncture the board.
Which test to use? For palletized shipments where boxes are stacked, ECT is the more relevant metric. For individual shipments handled by carriers like UPS, FedEx, or USPS, Mullen may be more meaningful. When in doubt, specify both ratings or consult with your box supplier to determine which is more appropriate for your application.
Size Optimization
Choosing the right box size is about more than just fitting your product inside. An oversized box wastes material, increases shipping costs, requires more void fill, and increases the risk of product damage during transit. An undersized box creates stress points that lead to failure. Here's how to find the sweet spot.
How to Calculate Optimal Box Size
Start by measuring your product at its widest, longest, and tallest points. Then add cushioning allowance on all six sides:
Box Length = Product Length + (2 x Cushion Thickness)
Box Width = Product Width + (2 x Cushion Thickness)
Box Height = Product Height + (2 x Cushion Thickness)
For most products, a cushion thickness of 1–2 inches on each side is sufficient. Fragile items may require 2–3 inches. Extremely fragile or high-value items often use a double-box method with 3+ inches of cushioning between the inner and outer boxes.
Always round up to the nearest standard box size. Using a standard size is almost always cheaper than ordering a custom dimension unless your volumes are very high (typically 500+ units).
DIM Weight Impact
Dimensional (DIM) weight pricing means carriers charge based on the size of the package, not just its actual weight. The DIM weight formula used by most major carriers is:
DIM Weight = (Length x Width x Height) / DIM Factor
The DIM factor is typically 139 for domestic shipments and 139 for international (UPS/FedEx). USPS uses different thresholds.
The carrier charges whichever is greater: actual weight or DIM weight. This means an oversized box for a light product can dramatically increase your shipping costs. For example, a 2 lb product in a 24x24x24 box has a DIM weight of approximately 99 lbs — meaning you'd pay for a 99 lb shipment despite only shipping 2 lbs.
Right-sizing your boxes is one of the single biggest opportunities for shipping cost reduction. Many businesses save 15–25% on shipping costs simply by moving to better-fitting box sizes.
Matching Box to Product
The right box depends on what you're shipping. Here is a practical framework for matching box specifications to your product characteristics.
Weight-Based Selection Chart
| Product Weight | Recommended Wall | Min ECT | Flute |
|---|---|---|---|
| Under 10 lbs | Single Wall | 23 ECT | B or E |
| 10-30 lbs | Single Wall | 29 ECT | C |
| 30-65 lbs | Single Wall | 32 ECT | C or BC |
| 65-95 lbs | Double Wall | 42 ECT | BC |
| 95-120 lbs | Double Wall | 48 ECT | BC |
| 120+ lbs | Triple Wall | 71+ ECT | ACA or BAB |
Fragility Considerations
Product fragility often matters more than weight when selecting a box. A 5 lb glass vase requires far more protection than a 50 lb bag of coffee beans. Consider these factors:
- ◆Impact sensitivity: Glass, ceramics, and electronics need A-flute or thick cushioning to absorb shocks during transit.
- ◆Compression sensitivity: Items that can be crushed (baked goods, produce) need boxes with sufficient stacking strength and should not be overpacked.
- ◆Moisture sensitivity: Products affected by humidity (electronics, dry food) benefit from wax-coated or moisture-resistant corrugated options.
- ◆Temperature sensitivity: Insulated corrugated containers with foam liners are available for cold-chain and temperature-sensitive products.
Cost Considerations
The cost of corrugated boxes depends on several interrelated factors. Understanding these factors helps you optimize your packaging spend without sacrificing protection.
Board Grade and Wall Type
Heavier board grades and multi-wall constructions cost more per unit. A 32 ECT single wall box might cost $1.50 while the same size in 48 ECT double wall could be $3.00+. Always spec the minimum strength required for your application.
Box Size and Style
Larger boxes use more material and cost more. Complex styles like die-cut and telescope boxes have higher tooling and setup costs. RSC boxes are almost always the most economical option per unit.
Order Quantity
Corrugated pricing drops significantly at volume breakpoints. Ordering 500 units might be 30-40% cheaper per unit than ordering 100. Annual blanket orders often unlock the best pricing tiers.
Printing and Branding
Plain brown boxes are the cheapest. Single-color flexo printing adds modest cost. Full-color litho-laminated printing adds significant cost but delivers premium shelf presence. Consider if your product needs branded packaging or if plain is acceptable.
New vs. Used
Used corrugated boxes in good condition typically cost 40-70% less than new equivalents. For internal shipments, warehousing, and non-customer-facing applications, used boxes offer exceptional value.
Shipping Costs
Remember to factor in the cost of shipping the boxes themselves. Flat-shipped RSC boxes are the most efficient. Pre-assembled or rigid boxes take up more truck space and increase freight costs.
Common Mistakes to Avoid
After decades in the corrugated industry, we've seen the same mistakes come up again and again. Avoid these pitfalls to save money and reduce damage.
Over-specifying box strength
Using 48 ECT double wall for a 10 lb product is wasteful. Match the box to the actual load requirements, not a worst-case scenario that will never occur.
Using one box size for everything
A "one size fits all" approach leads to excessive void fill, higher DIM weight charges, and more damage. Invest in 3-5 box sizes that cover 90% of your product range.
Ignoring DIM weight pricing
Many businesses focus on box cost while ignoring the much larger shipping cost impact. A $0.50 cheaper oversized box could cost $5.00 more in DIM weight surcharges per shipment.
Mixing up inside and outside dimensions
Inside dimensions determine what fits in the box. Outside dimensions determine DIM weight and storage space. Always specify which you mean when ordering, and measure accordingly.
Storing boxes improperly
Corrugated board loses up to 50% of its strength when exposed to moisture. Store boxes flat, off the ground, and in a dry environment. Never store boxes outside or in uncontrolled humidity.
Neglecting the tape seal
The strongest box in the world fails if it is not sealed properly. Use the H-tape method for maximum strength. Water-activated tape (WAT) provides the strongest seal and is tamper-evident.
Forgetting to test
Ship a few test packages before committing to a box specification for a new product. Real-world transit conditions often reveal issues that look fine on paper.
Need Help Choosing the Right Box?
Our packaging experts can recommend the ideal corrugated box for your specific application. Get a free consultation and quote.
Ready to Order?
Box Atlanta carries a full range of corrugated boxes in stock — new and used — with same-day availability in the Atlanta metro area. Custom sizes available with short lead times.