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Conex Box vs Shipping Container vs Storage Container: Is There a Difference?


April 30th, 2024

Kleenex or tissue. Soda or pop. Tennis shoes or sneakers. Conex box or shipping container.

Sometimes, we use different words to refer to the same thing. Over time, the words become interchangeable and are universally understood no matter whom we are speaking to. Often, the only difference in word choice is geographical or historical.


For example, "soda" is the preferred term in the Northeast, most of Florida, California and pockets of the Midwest around Milwaukee and St. Paul. "Pop" is what people say in the majority of the Midwest, and "coke," regardless of the flavor, is what people call it in the South.


Different Names For Shipping Containers

Whether you call them “shipping containers,” “storage containers,” “Conex (or Connex) boxes,” “ISO boxes,” or “sea containers” they all usually refer to the same thing – large metal, weather-resistant containers used to store or ship things. 


They are also all controlled by strict manufacturing guidelines to ensure they are universally interchangeable within common conex box dimensions to help streamline shipping.

Conex Boxes: The History Behind Them

  • CONEX is short for “Container for Export”, coined by the International Shipping Organization (ISO). Today, the word “Conex” is understood as a shipping term to refer to the way goods are shipped overseas.

  • CONEX containers are one of the most iconic developments in the history of transportation and logistics and they revolutionized the shipping industry.

  • The military saw the need to develop the early shipping containers in 1952. They saw the efficiencies of putting cargo in containers and not shipping items loose on ships.  

  • The commercial shipping industry took note in the mid-1960s and realized the need for standardization in container sizes and build specifications.

  • The International Maritime Organization established the International Organization of Standardization (ISO) to set universal guidelines that govern the manufacturing guidelines, sizes and capacity requirements of every shipping container made in the world. That is why they are sometimes referred to as “ISO boxes” or “ISO containers.”

The use of standardized steel and aluminum shipping containers actually began during the late 40s and early 50s, when commercial shipping operators and the U.S. military started developing shipping units. 


During World War II, the U.S. Army began experiments with containers to ship supplies to the front lines because cargo was being delayed at ports due to the time required by break bulk loading and unloading of ships, and supplies being stolen or damaged during transport.

"Shipping Containers" And "ISO Containers"

A “shipping container” is the most common way to describe a standard-sized box with strength suitable to withstand shipment, storage and handling while transporting goods from one place to another. Most shipping containers are made from Corten steel, a high-quality, corrugated steel that is susceptible to surface rust only, making it the ideal material to survive extreme weather.


In the shipping trade, the terms “container” and “shipping container” and “Conex” are understood to mean the same thing:

A large, reusable steel box designed to protect goods while they are shipped around the world.

These containers can withstand harsh environments and make it possible to ship materials using various modes of transportation – ship, rail or truck – without needing to unload the cargo each time the mode of transportation changes.

In the container industry, shipping containers are referred to as ISO containers or Intermodal Containers, which are large standardized shipping containers designed and built for intermodal freight transport. Intermodal shipping containers can be as large as 53-feet long. 

Shipping containers must conform to the International Maritime Organization’s ISO (International Organization for Standardization) specifications. These standards ensure consistent loading, transporting and unloading of goods in ports around the world. The ISO standardization also mandates that containers meet the size and durability requirements to allow them to stack safely and uniformly on ships and trains. 


ISO containers are inspected every 30 months by a certified inspector to ensure the container is within specifications. Used ISO containers for sale that are still certified for shipping are referred to as “Cargo Worthy” containers. 

Portable Storage Containers Are Not The Same As Conex Boxes

Another common way to refer to CONEX box containers is “storage containers” because they “store” goods during transport. However, it is not entirely accurate because portable storage containers are technically a different type of container.


Portable storage containers, sometimes called “moving pods" as popularized by PODS Moving & Storage Company, are light-weight storage and moving containers.


These personal storage and moving containers for sale come in sizes of 12ft, 16ft, and 20ft. They are 100% weather resistant with corrugated roofs to allow for optimal durability and water runoff. The floors are coated and sealed to provide a waterproof, non-slip, non-toxic, non-odorous surface. And they include forklift pockets, receiver tubes, d-rings, e-track and tie down rings, vents, and an ultra secure door locking mechanism.

Portable storage containers are great for temporary storage, moving, renovations, business storage, event storage, disaster relief, mobile offices, and much more.

Conex Box Dimensions

Container One’s conex box shipping containers come in 20-ft and 40-ft sizes, and are available in a variety of conditions to meet the specific needs of the customer. The standard 20-foot conex box weighs 4,500 pounds and has interior measurements of 20 feet long, 8 feet wide and 8.5 feet high. The door openings are 7 feet, 8 ½ inches wide and 7 feet, 5 ¾ inches high. The standard 40-foot Conex box weighs 8,500 pounds and has interior measurements of 40 feet long, 8 feet wide and 8.5 feet high. The door openings are 7 feet, 8 ½ inches wide and 7 feet, 5 ¾ inches high. 40-ft containers that are a foot taller, 9.5 feet high, are called high cube containers.

Check out other conex box sizes and dimensions in the video below:

Conex Box / Shipping Container Uses

Whether new or used, shipping containers provide a lot of value for businesses, farms, or homeowners. Because they’re made with sturdy weather-resistant steel, shipping containers for sale on the secondary market have countless uses. 


Here are some of the most common uses for conex boxes:

  • Construction storage

  • Personal storageCargo Worthy

  • Commercial building projects

  • Man caves/she-sheds (common use for 40-foot size)

  • Residential units, like custom homes or cabins (common use for 40-foot size)

  • Commercial units, like small business offices (common use for 40-foot size)

If you need onsite storage for tools, materials, or basic household goods, a conex box may be more cost effective than an equally sized shed. And it will likely last longer than a wooden shed.


Furthermore, if you want to build a small dwelling on a budget and with limited construction skills, shipping containers provide a unique and creative opportunity. Because of that, conex box homes are being built to help house homeless veterans.

Grades of Conex Boxes For Sale

Whether you call them Conex boxes or shipping containers, they are sold in a variety of conditions, and it’s important to know what those conditions are and if your intended use of the container aligns with the appropriate condition. These conditions determine the shipping container cost. These grade/conditions include:

  • New/1Trip: These are new containers that have only been loaded one time from the manufacturer. These are the highest condition of containers offered.

  • Wind and Water Tight (WWT): These units that are no longer certifiable to ship cargo on trains and ships. These are ideal for consumers who need a container to store personal items or anything that needs protection from harsh conditions.

  • Cargo Worthy (CW): These containers are guaranteed to pass re-certification to be loaded back on a ship or train. These can be packed with cargo and shipped across the world.

  • AS IS: These used conex containers will most likely have holes, floor damage and other fixable repairs, but are able to be used for storage.

So, when you need to protect, store or ship something and you need a steel box, call it what you will. We'll know what you mean. Because the name - whether it's a shipping container, Conex box or ISO container - is just as flexible as the potential uses for them. Whether building a shipping container home, or storing farming equipment, the uses are endless.


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