Size Guide

Complete Box Size Reference Guide

Everything you need to know about box sizes, strength ratings, flute types, and how to choose the right packaging for your products.

Standard Sizes Specialty Sizes Gaylord Sizes Strength Ratings How to Measure Dimensional Weight Flute Types Industry Sizes Terminology Weight Guide Stacking Metric Conversions Custom Sizes Selection Guide Printable Chart

Standard Corrugated Box Sizes

The most commonly used box dimensions in the industry. All sizes listed as Length x Width x Height in inches.

Size (L x W x H)	Common Uses	Max Weight (32 ECT)
4 x 4 x 4	Small parts, samples, jewelry	5 lbs
5 x 5 x 5	Cosmetics, supplements, USB drives	10 lbs
6 x 6 x 6	Candles, jars, small gifts	15 lbs
8 x 6 x 4	Books, DVDs, flat items	20 lbs
8 x 8 x 8	Mugs, small electronics, craft supplies	20 lbs
10 x 8 x 6	Retail products, electronics accessories	25 lbs
10 x 10 x 10	Flower pots, table lamps, toys	25 lbs
12 x 10 x 8	Shoes, clothing bundles, kitchenware	30 lbs
12 x 12 x 12	General purpose, medium items	35 lbs
14 x 10 x 10	Wine bottles (2-pack), taller goods	35 lbs
14 x 14 x 14	Small appliances, bulk clothing	40 lbs
16 x 12 x 8	Laptops, flat-screen monitors under 17 in	35 lbs
16 x 12 x 12	Tall items, bottles, decorative items	40 lbs
16 x 16 x 16	Helmets, medium appliances, houseware sets	45 lbs
18 x 14 x 12	Kitchen appliances, office supplies	45 lbs
18 x 18 x 16	Medium appliances, bulk storage	50 lbs
20 x 14 x 10	Printers, document boxes, monitors	50 lbs
20 x 20 x 20	Large items, multiple products	55 lbs
22 x 16 x 14	Computer towers, large kitchen gadgets	55 lbs
24 x 18 x 18	Linens, pillows, bulky soft goods	60 lbs
24 x 24 x 24	Moving, large storage, equipment	65 lbs
28 x 20 x 16	Sports equipment, bulky irregulars	65 lbs
30 x 24 x 24	Large equipment, oversized items	70 lbs
36 x 24 x 24	Furniture, artwork, industrial parts	75 lbs
40 x 30 x 20	Flat-pack furniture, signage, panels	75 lbs
48 x 24 x 24	Long items, lumber, pipe	80 lbs
48 x 40 x 36	Palletized freight, machinery covers	85 lbs
60 x 30 x 30	Mattresses (compressed), large fixtures	90 lbs

Specialty Box Sizes

Purpose-built boxes designed for specific items. These specialty shapes protect awkward, fragile, or oversized products that standard RSC boxes cannot safely accommodate.

Wardrobe Box

24 x 21 x 46

Hanging clothes, coats, formal wear. Includes metal bar for hangers.

Standard for residential and commercial moving.

Dish Pack / Barrel

18 x 18 x 28

Fragile dishware, glassware, ceramics. Extra thick double-wall construction.

Typically 350# burst or 48 ECT minimum.

Picture / Mirror Box

30 x 5 x 40 (adjustable)

Framed art, mirrors, flat-screen TVs, glass tabletops.

Telescoping design adjusts width from 3 to 6 inches.

Telescoping Box (Outer)

Variable — fits over inner

Adjustable-length protection for irregularly shaped items.

Two-piece design slides to exact length needed.

Lamp Box

12 x 12 x 40

Table lamps, floor lamp bases, tall vases, trophies.

Tall and narrow for upright fragile items.

File / Storage Box

15 x 12 x 10

Legal and letter-sized hanging files, documents, archives.

Reinforced handles; stackable design.

Wine Shipper (12-bottle)

19 x 13 x 16

Wine, spirits, craft beverages with divider insert.

Requires styrofoam or pulp dividers for safe transit.

Guitar Box

18 x 6 x 45

Acoustic and electric guitars, bass guitars, long instruments.

Needs interior padding; double-wall recommended.

Golf Club Box

13 x 13 x 50

Golf club sets, fishing rods, ski poles.

Extra-tall single-piece for long narrow items.

Bicycle Box

54 x 8 x 28

Partially disassembled bicycles, scooters, large frames.

Oversized flat design. Requires DIM weight adjustment.

Gaylord Box Sizes

Bulk containers designed for pallet-based storage and shipping. Dimensions in inches.

Size	Wall	Capacity	Pallet	Best For
40 x 30 x 30	Single	600 lbs	Half pallet	Light bulk storage
48 x 40 x 24	Single	700 lbs	Standard	Low-profile bulk items
48 x 40 x 36	Single	800 lbs	Standard	General bulk storage
48 x 40 x 36	Double	1,200 lbs	Standard	Heavy bulk items
48 x 40 x 48	Double	1,500 lbs	Standard	Tall bulk items
48 x 40 x 36	Triple	2,000 lbs	Standard	Heavy industrial
48 x 40 x 48	Triple	2,500 lbs	Standard	Max heavy-duty
48 x 48 x 48	Triple	2,500+ lbs	Custom	Oversized industrial

Box Strength Ratings (ECT)

Edge Crush Test measures how much stacking weight a box can handle. Higher ECT means stronger stacking performance.

ECT

32 ECT(200# burst)Max stack: 2,200 lbs

Standard single wall. Suitable for lightweight items up to 40 lbs. Most common for e-commerce and retail shipping.

ECT

44 ECT(275# burst)Max stack: 3,000 lbs

Heavy-duty single wall. For items 40-65 lbs. Better stacking strength for warehouse storage.

ECT

48 ECT(350# burst)Max stack: 3,400 lbs

Standard double wall. For items 60-80 lbs. Excellent crush resistance and stacking ability.

ECT

51 ECT(400# burst)Max stack: 3,600 lbs

Heavy double wall. For items up to 100 lbs. Superior protection for heavy or fragile products.

ECT

71 ECT(600# burst)Max stack: 5,000+ lbs

Maximum strength. Triple wall construction for the heaviest industrial loads over 100 lbs.

How to Measure a Box

Box dimensions are always listed in the order: Length x Width x Height. Understanding the difference between inner and outer dimensions is critical for proper fit.

Inner Dimensions (ID)

Measured from the inside of the box. Use inner dimensions when sizing a box for a specific product. This is the usable space.

Tip: Always allow 1-2 inches of clearance for cushioning material.

Outer Dimensions (OD)

Measured from the outside of the box. Use outer dimensions for calculating shipping costs, pallet configurations, and storage space.

Note: Outer dimensions are typically 0.5-1 inch larger than inner dimensions.

Measuring Steps

Length: The longest side of the box opening (top). Measure the longest horizontal edge.
Width: The shorter side of the box opening (top). Measure the shorter horizontal edge.
Height (Depth): The distance from the top opening to the bottom. Measure vertically from base to flap fold.

How to Calculate Dimensional Weight

Shipping carriers charge based on the greater of actual weight or dimensional (DIM) weight. Understanding DIM weight helps you choose boxes that minimize shipping costs.

The DIM Weight Formula

DIM Weight = (Length x Width x Height) / DIM Factor

All measurements are in inches. The DIM factor varies by carrier:

UPS / FedEx

139

DIM Factor (domestic)

USPS

166

DIM Factor (Priority Mail)

International

139

DIM Factor (standard)

Worked Examples

Small E-Commerce Box (12 x 10 x 8)DIM Weight = 6.9 lbs

12 x 10 x 8 = 960 cubic inches / 139 = 6.9 lbs. If the actual product weighs 4 lbs, the carrier bills you for 7 lbs (DIM weight rounded up).

Medium Box (18 x 14 x 12)DIM Weight = 21.8 lbs

18 x 14 x 12 = 3,024 cubic inches / 139 = 21.8 lbs. If the actual item weighs 10 lbs, you are paying for nearly 22 lbs of DIM weight.

Large Moving Box (24 x 24 x 24)DIM Weight = 99.4 lbs

24 x 24 x 24 = 13,824 cubic inches / 139 = 99.4 lbs. This shows why oversized boxes create huge DIM weight charges even for light items.

Pro Tips: Reducing DIM Weight Costs

Right-size your boxes. Using the smallest box that safely fits your product (with cushioning) is the most effective way to reduce DIM charges.
Use variable-height boxes or score-and-fold techniques to reduce box height after packing.
Consider poly mailers or padded envelopes for soft, non-fragile items under 3 lbs.
Consolidate multi-item orders into fewer, appropriately sized boxes rather than shipping items individually.
Negotiate DIM factors with your carrier. High-volume shippers can often secure DIM factors of 166 or higher with UPS/FedEx.

Flute Types Explained

The flute is the wavy layer inside corrugated board. Different flute profiles provide different properties.

Flute	Thickness	Flutes/ft	Description
A-Flute	5mm (3/16")	33/ft	Thickest flute. Best cushioning and stacking strength. Common in double wall constructions.
B-Flute	3mm (1/8")	47/ft	Fine flute with excellent printing surface. Ideal for retail packaging and die-cut boxes.
C-Flute	4mm (5/32")	39/ft	Most common flute type. Good balance of cushioning, strength, and printability.
E-Flute	1.5mm (1/16")	90/ft	Micro-flute. Excellent printing, thin profile. Perfect for mailer boxes and retail displays.
BC-Flute	6.5mm	Double	Double wall (B + C). Combines B-flute printability with C-flute cushioning. Standard for heavy-duty boxes.

Box Size by Industry

Different industries have different packaging requirements. Here are the most commonly requested box sizes for each major sector, along with selection tips specific to that industry.

E-Commerce & Retail

Online retailers need a range of sizes to match diverse product catalogs while minimizing DIM weight charges. Poly mailers work for soft goods; corrugated is essential for anything fragile.

6 x 6 x 6 — Small accessories, cosmetics, phone cases

10 x 8 x 6 — Books, electronics accessories, supplements

12 x 12 x 12 — General merchandise, subscription boxes

16 x 12 x 8 — Laptops, tablet bundles, small appliances

18 x 14 x 12 — Multi-item orders, gift sets

24 x 18 x 18 — Bulk clothing packs, large product bundles

Food & Beverage

Food-grade packaging demands cleanliness, insulation compatibility, and moisture resistance. For direct food contact, use only new or Grade-A boxes. Outer shipper boxes can be used-grade.

10 x 10 x 10 — Meal kits, small produce boxes, gift baskets

12 x 12 x 12 — Bakery items, coffee bean bags, spice sets

14 x 10 x 10 — Wine 2-pack, bottled sauce multipacks

19 x 13 x 16 — Wine 12-bottle shipper with dividers

24 x 18 x 18 — Bulk dry goods, snack packs, canned goods cases

48 x 40 x 36 (Gaylord) — Bulk produce, grain, ingredient storage

Manufacturing & Industrial

Industrial settings prioritize stacking strength and bulk capacity. Double- and triple-wall boxes protect heavy parts. Gaylords are the backbone of parts storage and inter-facility transport.

16 x 12 x 12 — Fasteners, small machined parts, tools

20 x 14 x 10 — Instrument panels, control units, motor parts

24 x 24 x 24 — Heavy equipment components, pump housings

36 x 24 x 24 — Large fabricated parts, sheet metal forms

48 x 24 x 24 — Pipe, extrusions, structural members

48 x 40 x 48 (Gaylord Triple) — Bulk scrap, heavy raw materials

Moving & Relocation

Movers benefit from a standardized set of sizes that stack uniformly in the truck. Specialty boxes for wardrobe, dishes, and pictures eliminate common damage claims.

16 x 12 x 12 (Small/Book Box) — Books, records, canned goods

18 x 18 x 16 (Medium) — Kitchen items, toys, general household

24 x 18 x 18 (Large) — Linens, pillows, lampshades, towels

24 x 24 x 24 (Extra Large) — Comforters, large toys, sports gear

24 x 21 x 46 (Wardrobe) — Hanging clothing with metal bar

18 x 18 x 28 (Dish Pack) — Fragile dishware with cell dividers

Box Terminology Glossary

RSC—Regular Slotted Container — The most common box style. All flaps are the same length and the outer flaps meet at the center.

FOL—Full Overlap — Similar to RSC but outer flaps extend the full width of the box, overlapping completely for extra strength.

HSC—Half Slotted Container — Like an RSC but with flaps on only one end. Used as trays or when top access is needed.

OPF—One-Piece Folder — A flat sheet scored and folded around the product. Common for books, frames, and flat items.

Die-Cut—Custom-shaped box cut with a steel die. Used for retail packaging, mailers, and products requiring precise fit.

Scored—A crease pressed into corrugated board to allow folding. Proper scoring prevents cracking and ensures clean folds.

Linerboard—The flat outer faces of corrugated board. Made from kraft paper (brown) or test liner (recycled fiber).

Fluting—The wavy middle layer of corrugated board that provides cushioning and structural support.

ECT—Edge Crush Test — Measures the stacking strength of corrugated board. Higher ECT = stronger stacking ability.

Burst Strength—Measured in lbs/sq inch. Tests puncture resistance. The older "#" rating system (e.g., 200# test).

Caliper—The thickness of the corrugated board, measured in thousandths of an inch (points).

DIM Weight—Dimensional Weight — A pricing method carriers use based on volume rather than actual weight. Calculated as (L x W x H) / DIM factor.

Knock-Down (KD)—A box shipped flat and unassembled. Saves storage space and shipping cost. Must be erected and taped before use.

Kraft—Unbleached brown paper made from wood pulp. The standard color of corrugated board. Stronger than recycled test liner.

SFC—Single Face Corrugated — One layer of fluting glued to one flat liner. Used for wrapping, cushioning, and surface protection.

Mullen Test—A burst strength test that measures how much pressure (PSI) corrugated board can withstand before rupturing. Also called the "pop" test.

Box Certificate—A round stamp printed on the box bottom showing manufacturer, board type, ECT or burst rating, and size limit. Required by carrier classification rules.

Pallet Pattern—The arrangement of boxes on a pallet for maximum stability and space utilization. Common patterns include column, interlocking, and pinwheel.

Void Fill—Material used to fill empty space inside a box to prevent product movement. Includes packing peanuts, air pillows, crumpled paper, and foam inserts.

Corrugating Medium—The paperboard sheet that gets fluted (shaped into waves). Together with linerboard, it forms the structure of corrugated board.

Weight Capacity Guide

Choosing the right box strength for your product weight prevents damage and optimizes cost.

Product Weight	Recommended Box Type	ECT Rating
Under 20 lbs	Single Wall (B or E flute)	32 ECT
20-40 lbs	Single Wall (C flute)	32-44 ECT
40-65 lbs	Single Wall (C flute) or Double Wall	44-48 ECT
65-80 lbs	Double Wall (BC flute)	48-51 ECT
80-100 lbs	Double Wall heavy-duty	51-71 ECT
100+ lbs	Triple Wall or Gaylord	71+ ECT

Stacking & Storage Guidelines

Proper stacking protects products, prevents costly damage claims, and maximizes warehouse space. These guidelines apply to both new and used corrugated boxes.

General Rules

Stack boxes only on flat, level surfaces to distribute weight evenly.
Never exceed the ECT stacking rating printed on the box certificate.
In humid conditions, reduce maximum stacking height by 30-50% as moisture weakens corrugated.
Stack heaviest boxes at the bottom, lightest on top.
Align boxes in columns (not brickwork) for maximum vertical crush resistance.
Use tier sheets (flat cardboard or plastic) between pallet layers to distribute load across all boxes in a row.
Avoid overhanging edges. Every box corner should be supported by the box or surface below it.
Fill boxes as close to capacity as possible. Partially filled boxes lose up to 70% of their compression strength.

Storage Environment

Keep cardboard dry. Moisture reduces compression strength by up to 50%.
Ideal storage: 70-75°F, 40-50% relative humidity.
Keep away from direct sunlight which degrades adhesives and weakens board.
Store flat (knocked-down) when possible to maximize warehouse space.
Elevate pallets off the floor with dunnage or pallet racks to prevent moisture wicking from concrete.
Leave at least 18 inches of clearance from sprinkler heads per fire code requirements.
Rotate stock using FIFO (first in, first out) to prevent prolonged compression on bottom boxes.

Pallet Stacking Patterns

The arrangement of boxes on a pallet affects both stability during transport and compression strength in storage.

Column Stack

Each box sits directly on top of the one below. Maximum compression strength. Best for storage and static pallets.

Interlock / Brick

Alternate layers rotated 90 degrees. Better lateral stability for transport. Reduces compression strength by approximately 40%.

Pinwheel

Boxes arranged in a rotating pattern around a center. Good for non-uniform box sizes and mixed pallets.

Maximum Stack Heights by ECT

These are guidelines for standard, fully packed boxes in ideal storage conditions (below 50% relative humidity).

ECT Rating	Max Stack (Ideal)	Max Stack (Humid)	Typical Pallet Layers
32 ECT	2,200 lbs	1,100-1,500 lbs	4-5 layers
44 ECT	3,000 lbs	1,500-2,000 lbs	5-6 layers
48 ECT	3,400 lbs	1,700-2,300 lbs	6-7 layers
51 ECT	3,600 lbs	1,800-2,500 lbs	7-8 layers
71 ECT	5,000+ lbs	2,500-3,500 lbs	8-10 layers

Used Box Stacking Considerations

Used boxes lose some compression strength with each use cycle. Here is how to account for that:

Grade A: Retain approximately 90-95% of original compression strength. Stack per standard guidelines.
Grade B: Retain approximately 75-85% of original strength. Reduce maximum stack weight by 15-20%.
Grade C: Retain approximately 60-70% of original strength. Reduce maximum stack weight by 30-40%.
Grade D: Retain approximately 40-55% of original strength. Use for single-layer storage only or stack no more than 3 layers high.

How to Choose the Right Box

Step 1: Determine Product Dimensions

Measure the length, width, and height of your product. Add 1-2 inches to each dimension for cushioning material (bubble wrap, foam, packing peanuts).

Step 2: Consider Product Weight

Match your product weight to the appropriate ECT rating. Over-engineering wastes money; under-engineering risks damage. Use the weight capacity guide above.

Step 3: Account for Shipping Method

Parcel shipping (UPS, FedEx) requires less protection than freight. International shipping needs stronger boxes than domestic. Consider the journey your box will take.

Step 4: Factor in Storage

If boxes will be stacked or stored long-term, choose a higher ECT rating. Factor in environmental conditions like humidity and temperature.

Step 5: Consider Presentation

Customer-facing shipments may warrant A-grade or new boxes. Internal moves and storage can use C or D grade for maximum cost savings.

Metric Conversion Table

For international customers shipping to or from the United States, here is a quick reference for converting standard US box sizes to metric measurements. Volume is calculated using inner dimensions.

Inches (L x W x H)	Centimeters (approx.)	Volume (Liters)
4 x 4 x 4	10 x 10 x 10	1.0 L
6 x 6 x 6	15 x 15 x 15	3.5 L
8 x 8 x 8	20 x 20 x 20	8.4 L
10 x 10 x 10	25 x 25 x 25	16.4 L
12 x 12 x 12	30 x 30 x 30	28.3 L
14 x 14 x 14	36 x 36 x 36	44.8 L
16 x 16 x 16	41 x 41 x 41	67.1 L
18 x 18 x 18	46 x 46 x 46	95.6 L
20 x 20 x 20	51 x 51 x 51	131 L
24 x 24 x 24	61 x 61 x 61	226 L
30 x 30 x 30	76 x 76 x 76	442 L
36 x 36 x 36	91 x 91 x 91	764 L
48 x 40 x 36	122 x 102 x 91	1,129 L

Conversion Formulas

Inches to CM: Multiply inches by 2.54

Cubic inches to Liters: Divide cubic inches by 61.024

Pounds to KG: Multiply pounds by 0.4536

Custom Size Options

When standard sizes do not fit your product, Portland Boxes offers custom sizing solutions. We can source or fabricate boxes to your exact specifications, available in both new and select used options.

Custom New Boxes

Available in any dimension up to 60 x 48 x 48 inches.
Choice of single, double, or triple wall construction.
Custom printing available (1-4 color flexographic).
Minimum order: 100 units for standard RSC, 250 for die-cut.
Lead time: 7-14 business days for standard custom, 3-4 weeks for printed.
Pricing decreases significantly at 500, 1,000, and 5,000+ units.

Custom Used / Trimmed Boxes

We can score and trim existing used boxes to your required height.
Available when standard used sizes are close but not exact.
Reduces height only (cannot reduce length or width).
No minimum order. Available same-day in most cases.
Cost: small trimming fee on top of the used box price.
Ideal for businesses that need a specific height but flexible on L x W.

How to Request a Custom Size

Measure Your Product

Record exact L x W x H of the item including any protrusions, then add 1-2 inches per side for cushioning.

Choose Box Strength

Determine the ECT rating or wall type needed based on product weight and shipping conditions.

Contact Our Team

Email or call with your dimensions, quantity, strength requirements, and desired timeline.

Receive Your Quote

We will provide pricing, lead time, and available options within one business day.

Need a Printable Size Chart?

Download our complete size reference chart as a printable PDF. Keep it posted in your warehouse, shipping station, or office for quick reference when ordering boxes.

Request PDF via Email Need a Custom Size?

The chart includes all standard sizes, specialty sizes, gaylord dimensions, and strength ratings in a single reference sheet.