Used Container Grades Explained: Cargo-Worthy, Wind & Watertight, As-Is

Every listing of used shipping containers for sale comes with a grade, and the grade drives the price more than anything except size. Grades can feel like jargon, but there are really only four you need to know, and each one tells you what the container is still fit to do.

This guide explains each grade, who decides it, and which one makes sense for your project. When you know which grade you need, compare our used shipping containers for sale in 20ft, 40ft and 45ft.

Why used containers are graded

Shipping containers spend years at sea, stacked on ships and moved by cranes, trucks and trains. When a shipping line or leasing company retires a container, it gets inspected and sorted by what it can still safely do. The grade isn't about looks: it describes the container's structure and weathertightness.

That's why a cargo-worthy container, which can still go to sea, can look more battered than a wind and watertight one. Dents, surface rust and faded paint are cosmetic. Holes, rot and a damaged frame are not.

The four grades

IICL or premium

The Institute of International Container Lessors (IICL) publishes inspection standards that leasing companies use when containers come off lease. A unit described as "IICL" or "premium" is a used container in very good condition: straight panels, a sound floor, working doors and minimal repairs. It's the best used grade and the closest to new.

Best for: conversions on a budget, customer-facing sites, buyers who want a used box that looks tidy.

Cargo-worthy (CW)

A cargo-worthy container is structurally sound enough to carry cargo by sea. The frame, corner posts and corner castings are intact, the floor can take a load, and the doors close and seal. It may have dents, patches and surface rust.

A container can be surveyed by an independent marine surveyor, who issues a cargo-worthy certificate. You'll need that if you plan to ship goods in it on a vessel, along with a valid CSC safety approval plate.

Best for: shipping your own cargo overseas, and storage where you want extra confidence in the structure.

Wind and watertight (WWT)

A wind and watertight container keeps out wind and rain. It has no holes, the doors close and the seals work. It isn't certified for ocean shipping, often because of cosmetic or minor structural issues that don't matter on land.

Best for: on-site storage at home, on farms, on job sites and at businesses. For most storage buyers, this is the best value.

As-is

An as-is container is sold with known problems: pinholes or rust-through, soft floor sections, stiff or damaged doors, or a bent part. It's the cheapest grade because you're taking on the repairs.

Best for: projects where you'll cut, patch or modify the box anyway, or uses where a leak doesn't matter. Inspect carefully or get detailed photos first.

The grades side by side

Who decides the grade?

In most sales, the seller grades the container after inspecting it at the depot. Reputable sellers grade consistently and will put the grade in writing. A few things to know:

• Grading isn't regulated for storage sales, so "grade A" or "storage grade" can mean different things to different sellers. Ask what a term means.
• Cargo-worthy certificates come from independent surveyors and are what shipping lines and freight forwarders look for.
• The CSC plate on the door shows the container's safety approval and manufacture date. Containers in international service must also be examined periodically, so ask whether the plate is current if you plan to ship.

Which grade do you need?

• Storing goods on your property? Wind and watertight. Spend the savings on a lock box and good ground preparation.
• Shipping your own goods overseas? Cargo-worthy, with a survey certificate if your shipping line or forwarder requires one.
• Converting it into an office, studio or home? One-trip new or IICL. Straight walls and a clean floor make insulation and fit-out much easier. Compare new conex containers.
• Cutting it up for a project on a tight budget? As-is can work, as long as the parts you're keeping are sound.

How to confirm a grade before you buy

1. Get the grade in writing on your quote or invoice.
2. Ask for photos of the actual unit, including the roof, floor, door seals and CSC plate.
3. Match the unit number in the photos to your paperwork.
4. Do the light test on delivery: close yourself inside and look for daylight.
5. Check the doors open, close and lock smoothly.

FAQ

Is cargo-worthy better than wind and watertight?

Structurally, yes: a cargo-worthy container can still go to sea. But for storage, a wind and watertight container does the same job for less money.

Can a wind and watertight container be shipped overseas?

Not without a survey, and many won't pass one. If you plan to ship, buy cargo-worthy and get a certificate.

Does "as-is" mean the container leaks?

Not necessarily, but it might. As-is means the seller isn't promising it's watertight. Ask what the known problems are and see photos.

Do used container grades describe appearance?

No. Grades describe structure and weathertightness. Dents, surface rust and faded paint are normal on used containers of every grade.