Shipping Container Grades Explained: New, One-Trip, Cargo-Worthy, WWT and As-Is
What each container grade really means, how to inspect a used box, and which grade to buy for storage, shipping or a container home.
Updated October 25, 2026 · 5 min read
Container grades compared
| Grade | What it means | Best for |
|---|---|---|
| New / one-trip | Built recently, shipped once with cargo. Few or no dents, clean floor. | Homes, offices, retail, anything visible |
| Cargo-worthy (CW) | Used, but structurally sound enough to ship cargo. Often has a valid CSC plate. | Shipping your own goods, long-term storage |
| Wind & watertight (WWT) | Used, keeps out wind and rain, but may not be certified for shipping. Dents and surface rust. | Ground storage on farms, job sites, backyards |
| As-is | Sold without promises. May leak or have holes. | Parts, projects, buyers who inspect in person |
How to inspect a used container
- Step inside, close the doors and look for light coming through the roof or walls.
- Check the doors open and close easily and the rubber seals are not torn.
- Look at the floor for soft spots, stains or holes.
- Check the roof for dents that hold water, and the corners for heavy rust.
- Ask for photos of the exact unit with its container number if you can’t visit.
Which grade should you buy?
For simple storage, a WWT box is usually the best value. For a home, office or anything you will modify, start with a one-trip box — fixing rust and dents later costs more than the price difference. If you plan to ship goods overseas, ask for cargo-worthy with a valid CSC plate.
Next: see price estimates by grade or find sellers near you.
Find container companies near you
Browse container sellers, rental companies and depots by state and city, then contact them directly. Read our size, grade and price guides first.
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Find container companies near you
Sellers, rental companies and depots by state and city.
Frequently asked questions
Is there an official grading system?
No single law sets the grades. Terms like “cargo-worthy” and “WWT” are industry labels, and sellers use them differently. Ask the seller to define the grade in writing.
What is a CSC plate?
The Convention for Safe Containers plate on the door shows the maker, date and safety approval. A valid CSC is needed to ship cargo internationally; it does not matter for ground storage.
Can a used container be painted?
Yes. Clean off rust, prime with a metal primer and use a paint made for steel. Many sellers offer painting for a fee.
Related guides
- How Much Does a Shipping Container Cost? 2026 Price Estimates by Size and Grade
- Shipping Container Sizes: 10ft, 20ft, 40ft and High-Cube Dimensions Compared
- Rent vs Buy a Storage Container: Which Costs Less?
This guide is general information, not legal advice. Rules and rates change — confirm permits with your city or county and get written quotes before you buy.