20GP vs 40GP vs 40HC Container: Which Size Do You Need?

You're placing your first FCL (Full Container Load) order and your forwarder asks: "Do you want a 20GP, 40GP, or 40HC?" You have 28 CBM of cargo. You're not sure which container fits that, what the difference between 40GP and 40HC is, or which one gives you the best value for money.

Getting this decision wrong is expensive. Book too small and your cargo doesn't fit — rebooking costs money and delays your shipment. Book too large and you pay for space you don't need. This guide gives you the exact numbers to make the right call.

What the Abbreviations Mean

Before the comparison, here's what the codes actually stand for:

• GP — General Purpose. Standard height container: 8 feet 6 inches (2.591 m) external height.
• HC — High Cube. Taller container: 9 feet 6 inches (2.896 m) external height — exactly 1 foot taller than a GP.
• 20GP — 20-foot General Purpose container. The shortest, smallest standard container.
• 40GP — 40-foot General Purpose container. Double the length of a 20GP, standard height.
• 40HC — 40-foot High Cube container. Same length as 40GP but taller. This is the most commonly used container in modern manufactured goods trade.

You may also see "40HQ" — this is simply the Asian market abbreviation for the same 40HC container. HC and HQ are identical containers.

Internal Dimensions: The Numbers That Matter

External dimensions are the overall container size. What matters for cargo is the internal usable space:

The 40HC is identical to the 40GP in length and width. The only difference is the extra 30.5 cm (12 inches) of internal height. That extra height is what allows tall cargo to fit — and it adds approximately 8.8 m³ of theoretical volume to the container.

Note: These are ISO standard internal dimensions. Actual dimensions may vary slightly by manufacturer and container age. Always confirm with your carrier or container operator for precision load planning.

Usable CBM: Theoretical vs Practical

The theoretical maximum CBM is simply internal L × W × H. But this is never fully achievable in practice because of:

• Structural braces and corner fittings that reduce usable floor area near the corners
• Door end frames that slightly reduce usable length
• Safe packing requirements — cargo must be secured to prevent shifting
• Weight limit constraints: for heavy cargo, the container is full by weight before it's full by volume

For planning purposes, use the conservative end of the practical range: 25 CBM for 20GP, 55 CBM for 40GP, 64 CBM for 40HC. This leaves you a buffer for packing inefficiencies and irregular cargo shapes.

Weight Limits and Payload

Maximum Gross Weight (MGW) for standard ISO containers is 30,480 kg. Subtract the container's own tare weight to get the maximum payload:

This reveals a critical insight: despite being twice as long, the 40GP and 40HC don't have significantly more payload capacity than a 20GP. In fact, their heavier tare weight gives them less payload.

Consequence for heavy cargo: If you're shipping dense, heavy goods — tiles, stone, machinery parts, metal components — you may hit the weight limit of a 40GP before filling its volume. In this case, two 20GP containers often makes more sense than one 40GP, because 20GPs have the best payload-to-length ratio.

Cost-Per-CBM: Which Container Is Most Efficient?

Ocean freight rates fluctuate by trade lane and season. But the relative cost relationship between container types is remarkably consistent. Using typical Asia–Europe rates as an illustration:

When fully loaded, the 40HC delivers the best cost per CBM — typically 35–40% better than a 20GP. This is why the 40HC dominates modern container trade for manufactured goods, garments, consumer electronics, and similar products.

Critical caveat: The 40HC only wins on cost per CBM when it is actually full. A 40HC at 30% capacity is significantly more expensive per CBM than LCL. The efficiency advantage only materialises when the container is loaded to 80%+ capacity.

How Many Pallets Fit in Each Container?

For palletised cargo, the floor footprint is the key constraint:

For light cargo that can be double-stacked, a 40HC significantly outperforms a 40GP in pallet count. With 2.698 m internal height, you can double-stack pallets up to approximately 100–110 cm cargo height per layer, which accommodates most retail merchandise.

When to Choose Each Container

Choose a 20GP when:

• Your cargo is heavy and dense (machinery, metals, ceramics, stone products) and you're likely to hit weight limits before filling the volume of a 40-footer.
• You have 15–26 CBM of cargo and the 20GP FCL rate is competitive with LCL for your trade lane.
• Your destination has road or bridge weight restrictions that limit loaded truck gross weight — a 40HC fully loaded with heavy cargo may exceed permitted axle loads.
• Port infrastructure at your origin or destination handles 20-foot containers more efficiently (less common, but relevant at some regional ports).

Choose a 40GP when:

• Your cargo is between 40–58 CBM at standard density, fitting within the 40GP's usable height of 2.39 m.
• All items fit comfortably within 2.3 m stacking height and there's no need for the extra height a 40HC provides.
• 40HC availability is limited on your trade lane — this is less common but relevant in some regional port pairs.

Choose a 40HC when:

• Your cargo is between 58–68 CBM and benefits from the extra height.
• You have tall cargo — vehicles, large machinery, display fixtures, retail shelving, items over 2.3 m in height.
• You want the best cost-per-CBM for light to medium density manufactured goods, garments, retail merchandise, or consumer electronics.
• You're shipping garments on hangers (GOH) — 40HC is the standard container for this mode.

The LCL vs FCL Breakeven

No container analysis is complete without the LCL comparison. FCL only makes financial sense when you're loading enough cargo to justify the flat container rate. On major trade lanes:

• Asia–Europe: FCL (20GP) typically becomes competitive at 12–15 CBM
• Asia–US West Coast: FCL competitive at 10–14 CBM
• Intra-Asia routes: FCL can be competitive at 8–10 CBM due to low container rates

Below these thresholds, LCL is almost always cheaper despite its higher per-CBM rate, because you're not paying for unused container space.

Frequently Asked Questions

Is 40HC the same as 40HQ?

Yes, completely identical. HC (High Cube) and HQ (used in parts of Asia, sometimes called "High Quality") refer to the same container: 40-foot length, 9-foot 6-inch external height. The terminology varies by carrier, region, and era. When booking, confirm the internal height to be sure you're getting the taller container.

Can I mix cargo from multiple suppliers in one FCL?

Yes — this is called a buyer's consolidation. You arrange pickup from multiple suppliers and consolidate into a single FCL container, typically at a nearby CFS (Container Freight Station). This is common for importers sourcing from multiple factories in the same region. Your freight forwarder or a local consolidation agent can coordinate this.

What is the maximum load height in a 40HC container?

Internal height is 2.698 m. Practical maximum load height, allowing for floor packing boards and strapping/blocking, is around 2.55–2.60 m. For any items approaching or exceeding this, verify clearance before booking. Taller cargo may require open-top or flat-rack containers.

How do I confirm my cargo will fit before booking?

Calculate the total CBM of your shipment first, then compare it against the practical usable CBM of each container type. As a simple rule: if total CBM is under 25, a 20GP can work; under 55, a 40GP; under 65, a 40HC. For irregular or tall cargo, consult your forwarder or run a container load plan.

Use our Container Load Calculator to see exactly how many of your cartons fit into a 20GP, 40GP, or 40HC — with full CBM utilisation breakdown and weight limit comparison.