Shipping container dimensions and types

Every container booking starts with the same two questions: what are the containers’ actual internal dimensions, and how much of that space can your cargo really use? This guide answers both — a reference table below lists internal dimensions, capacity and maximum payload for the container types used in most sea freight, and the sections before it explain how to read those numbers when planning a load.

What is container loading?

Container loading is the process of deciding how a shipment is arranged inside a shipping container: which cargo goes in which container, where each item sits, which way round it faces, and what stacks on top of what. Done well, it fills the container to the limit that actually binds - volume, payload, or the door opening - while keeping the load stable enough to survive the voyage. Done badly, it ships air, or it ships damage.

A container loading calculator turns that from a judgement call into a computation. You give it your cargo list and your available equipment, and it returns a load plan: a 3D arrangement, a container count, and step-by-step instructions the people doing the physical stuffing can follow.

The three limits that decide a load

Almost every container ships out constrained by one of three things, and knowing which one is binding tells you what to change.

Volume

The container runs out of space before it runs out of weight. Typical for light, bulky goods - furniture, packaging, empty containers-within-containers. The lever here is geometry: better orientation, tighter stacking, or a taller high-cube container.

Payload

The container hits its maximum weight with space to spare. Typical for dense cargo - machinery, liquids, tiles, paper. Adding volume-efficiency gains you nothing; the answer is usually splitting the load across more containers, or moving to equipment with a higher payload rating.

The door opening

The most commonly missed one. A container’s door is smaller than its interior, so cargo that fits inside on paper may not be able to get in. Over-height or over-width pieces need an open top or a flat rack, where the cargo is loaded from above or from the side instead of through the doors.

Why stability matters as much as fit

A container that is packed full but badly balanced is a problem in transit. Weight concentrated at one end shifts the centre of gravity away from the middle, which affects how the container behaves when it is lifted by crane, sits on a chassis, and is stacked on a vessel. Some ports and carriers will refuse a container whose centre of gravity is too far off-centre.

The same applies inside the load. Heavy items belong at the bottom, lighter items on top, and cargo that cannot take weight on it needs to be marked as such so nothing gets stacked onto it. These are constraints a spreadsheet cannot check for you and a person doing it by eye will eventually get wrong on a busy day.

Cargo-Planner applies all of this automatically - it keeps the centre of gravity within tolerance, respects stacking and orientation rules per item, and checks that everything it loads can physically get through the door of the container it assigned it to. The table below has the numbers to plan against, and the calculator underneath turns them into an answer for your own cargo.