20ft vs 40ft Containers: Costs, Capacity & What Fits Inside

When Australians prepare to move household goods or ship commercial freight overseas, one of the first questions is container size. Do you need a 20-foot container, or should you opt for the larger 40-foot unit? The choice affects not only costs but also how efficiently you can pack, insure, and transport your cargo.

Shipping containers are the backbone of global logistics, designed to standardised dimensions under the ISO framework so they can be stacked, craned, and secured seamlessly across ships, trucks, and rail. But the two most common options—20ft and 40ft—offer very different advantages depending on the nature of your shipment.

Dimensions and Capacity

• 20ft Container

  • External: ~6.06m long, 2.44m wide, 2.59m high

  • Internal capacity: ~33 cubic metres

  • Weight allowance: generally up to 28 tonnes

  • Typical use: heavy cargo like machinery, metals, or dense goods that fill the weight limit before the space.

• 40ft Container

  • External: ~12.19m long, 2.44m wide, 2.59m high

  • Internal capacity: ~67 cubic metres

  • Weight allowance: slightly less per cubic metre compared with a 20ft due to maximum gross weight limits

  • Typical use: household removals, furniture, textiles, consumer goods—bulky but relatively lighter cargo.

In essence, a 40ft container offers double the space but not double the weight allowance. For shipments dominated by volume rather than mass, the 40ft is the more economical option.

Cost Comparisons

Freight charges depend on route, demand, and seasonality, but broadly:

• 20ft containers are cheaper to book upfront. However, if your cargo nearly fills two 20ft units, consolidating into a single 40ft is often more cost-effective.

• 40ft containers command higher base rates but offer better value per cubic metre. They also reduce handling complexity compared to managing multiple smaller boxes.

Beyond freight, port charges, wharfage, and handling fees can vary depending on container size, so obtaining itemised quotes is essential.

What Fits Inside

A simple way to visualise capacity:

• 20ft Container

  • Small 2–3 bedroom household move

  • One vehicle plus some personal effects

  • Palletised cargo: around 10–11 standard pallets (1.2m x 1.0m)

• 40ft Container

  • Large 4–5 bedroom house, including appliances and furniture

  • Two small cars or one SUV plus personal items

  • Palletised cargo: around 21–24 pallets depending on configuration

High Cube (HC) variants, slightly taller at 2.89m, are also available and popular for goods that are bulky but not excessively heavy.

Choosing Between 20ft and 40ft

The decision rests on three main factors:

1. Volume vs Weight – Are you shipping dense machinery or lighter household items?

2. Budget – Does your quote for a 40ft provide savings compared to using two 20ft containers?

3. Handling – Fewer containers mean fewer points of potential delay, customs checks, or storage costs.

If in doubt, freight forwarders often recommend conducting a pre-move survey. This helps estimate cubic metres precisely and avoid paying for unnecessary unused space.

Why It Matters for Australian Shippers

From Sydney to Singapore or Melbourne to London, transit costs mount quickly if container space is mismatched to cargo. A family relocating overseas may benefit from the capacity of a 40ft, while exporters of mining equipment often prefer the sturdier economics of a 20ft.

Making the right call upfront saves money, reduces handling risks, and ensures smoother customs clearance at both ends.

Final Word

Selecting between 20ft and 40ft shipping containers is more than a question of size—it is about optimising cost, cargo safety, and logistics efficiency. Before locking in your booking, compare detailed quotes, factor in marine insurance, and ensure your cargo is packed and documented to international standards.

For a broader look at containerised shipping, see our pillar guide to international freight from Australia.