Short answer: Cargo Worthy (CW) containers are inspected and certified for international ocean shipping; Wind & Watertight (WWT) containers are weatherproof but not certified for export. Choose CW if you want a guaranteed structural inspection or might ship the unit; choose WWT for cheaper, reliable ground storage.
A Cargo Worthy container has passed inspection by a licensed maritime surveyor, who checks structural integrity, door seals, and floor condition, then certifies the unit fit to carry cargo on an international vessel. That certification is a formal, standardized process — it's the closest thing the used-container market has to an independent quality guarantee.
A WWT container has been visually inspected by the depot operator to confirm the doors seal properly and there are no holes or breaches that would let weather in. There's no standardized inspection body behind the WWT label the way there is for CW, which means quality can vary meaningfully between suppliers — one depot's WWT grade might exceed another's. Buying from an established, reputable seller matters more at this grade than any other.
CW containers typically cost several hundred dollars more than WWT units of the same size, reflecting the cost and rigor of the formal inspection. On this site, a 20ft CW runs $2,400 versus $1,600 for 20ft WWT.
If you're storing tools, inventory, or equipment on your own property and never plan to ship the box itself, WWT saves money without sacrificing weatherproofing. If you want the strongest structural guarantee — especially for a conversion project like an office or home shell where structural soundness matters long-term — go Cargo Worthy.
See our Cargo Worthy container listings or Wind & Watertight listings for exact current pricing.
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