Industrial & logistics · Reference
Corrugated cartons are measured Length × Width × Depth (internal dimensions). There is no universal size table — boxes are made to order — but the form is standardized by FEFCO style codes (0201 RSC is the most common) and A/B/C/E/F flute grades.
A corrugated box is specified by three internal dimensions in Length × Width × Depth order; depth is the upright side of the opening.
| FEFCO code | Style (acronym) | Description |
|---|---|---|
| 0201 | Regular Slotted Container (RSC) | One piece of board; all flaps the same length, the two outer flaps half the container's width so they meet at the center; ships flat. The most common box style. |
| 0200 | Half Slotted Container (HSC) | An RSC without the top flaps. |
| 0202 | Overlap Slotted Container (OSC) | Outer flaps partially overlap. |
| 0203 | Full Overlap Slotted Container (FOL) | Outer flaps overlap the full width; extra stacking strength. |
| 0410 | Five Panel Folder (FPF) | A fifth panel closes the box; multiple board layers at each end for long items. |
Source: Fibre Box Association — Box Styles Basics (FEFCO / International Fibreboard Case Code)
| Flute grade | Thickness (nominal) | Flutes per ft | Typical use |
|---|---|---|---|
| A flute | ~3/16 in (4.8 mm) | 33 ± 3 | Thickest; cushioning and stacking strength for fragile or heavy items. |
| B flute | ~1/8 in (3.2 mm) | 47 ± 3 | Crush-resistant with a smooth print surface; cans, trays, displays. |
| C flute | ~5/32 in (4.0 mm) | 39 ± 3 | Most widely used in the US; default for general shipping and e-commerce. |
| E flute | ~1/16 in (1.6 mm) | 90 ± 4 | Micro-flute; flat surface for high-quality retail print. |
| F flute | ~1/32 in (0.8 mm) | 125 ± 4 | Thinnest; premium and small retail packaging. |
| Box | Inside L × W × D (in) | Inside L × W × D (mm) | Outside L × W × D (in) |
|---|---|---|---|
| Small Flat Rate Box | 8 5/8 × 5 3/8 × 1 5/8 | 219 × 137 × 41 | 8 11/16 × 5 7/16 × 1 3/4 |
| Medium Flat Rate Box | 11 × 8 1/2 × 5 1/2 | 279 × 216 × 140 | 11 1/4 × 8 3/4 × 6 |
| Large Flat Rate Box | 12 × 11 3/4 × 5 1/2 | 305 × 298 × 140 | 12 1/4 × 12 × 6 |
Source: USPS Postal Store — Priority Mail Flat Rate box pages
A spec table only helps if the buyer reads it. Many don't — shoppers routinely try to judge a product's size straight from the images, and wrong size or fit is the most-cited reason things get returned. The fix is to mark the real dimensions on the photo itself, where the buyer is already looking.
SizeMarker snaps dimension lines to the corrugated carton's edges and exports at Amazon or Alibaba size, so the measurement is accurate and legible — not a guess typed over the picture. That answers the size question up front and cuts pre-sale questions and size-driven returns.
Related: Industrial spec diagram maker · Product spec sheet maker · Best tools to add dimensions to product photos · Ecommerce returns & size statistics
There isn't one — corrugated boxes are largely made to order. What is standardized is the box style (e.g. FEFCO 0201 RSC) and the flute grade; carriers and marketplaces publish their own fixed tiers and limits.
By three dimensions in Length × Width × Depth order, and conventionally by internal dimensions so the product fits. USPS, for example, publishes both inside and outside dimensions for its Flat Rate boxes.
The Regular Slotted Container: one piece of board where all flaps are the same length and the two outer flaps are half the container's width so they meet at the center. The Fibre Box Association calls it the most common box style.
C flute (~5/32 in / 4.0 mm) is the most widely used for general shipping. B flute (~1/8 in / 3.2 mm) adds rigidity and print quality, while E and F micro-flutes (~1.6 mm and ~0.8 mm) suit retail packaging.
As of June 20, 2025, US FBA boxes may be up to 36 × 25 × 25 in and 50 lb (a single oversized item can exceed the length). Amazon Warehousing & Distribution (AWD) shipments stay within 25 × 25 × 25 in and 50 lb.
Inside dimensions are: Small 8 5/8 × 5 3/8 × 1 5/8 in, Medium 11 × 8 1/2 × 5 1/2 in and Large 12 × 11 3/4 × 5 1/2 in (roughly 219 × 137 × 41 mm, 279 × 216 × 140 mm and 305 × 298 × 140 mm).
Every figure on this page is traced to a named source, linked under each table. Standard sizes come from published standards and established industry references; where a size is a typical range or varies by manufacturer, we say so. Sizes vary by region, model and revision — treat these as the standard reference, and confirm the exact spec of the item you are selling.
Mark accurate dimensions and specs on your product photos in minutes. Free to start.
Start free · 30 credits on sign-up