Container Load Calculator — 20GP, 40GP & 40HC

Container Internal Specifications

Internal dimensions vary slightly by container manufacturer. These figures are standard industry averages used for planning purposes. Always confirm with your shipping line before booking.

How to Use This Calculator

1. Select your container type — 20GP, 40GP, 40HC, or 45HC using the buttons above.
2. Enter your carton dimensions — length, width, and height in your preferred unit, plus the quantity of cartons.
3. Add the weight per carton — the tool will flag a warning if your total cargo weight exceeds the container's payload limit.
4. Read your result — you'll see total cargo CBM, fill percentage, remaining space, and how many containers you need.

When You're Choosing Between 20ft and 40ft

If your cargo is under 25 CBM and under 25,000 kg, a 20GP is usually the right call — smaller containers move faster through yards and are easier to fill efficiently. Above 25 CBM, a 40GP or 40HC starts making more economic sense because the cost per CBM is lower.

The 40HC is worth the slight premium over a 40GP whenever your cargo stacks above 2.39 m, or when you're close to filling a 40GP and need the extra 8.8 CBM buffer. Booking the wrong size costs you in rebooking fees, demurrage, or paying for unused space — run this calculator before you confirm.

Understanding Container Utilisation

At 85–90% fill, FCL shipping is typically more cost-effective than LCL. Below 60%, LCL is usually cheaper. But utilisation alone doesn't tell the full story: weight, stackability, and cargo type all affect whether you can actually load to the calculated percentage. Use the fill percentage from this tool as your planning baseline, then apply a 10–15% inefficiency buffer for real-world loading.

Frequently Asked Questions

How many CBM fit in a 20ft container?

A 20GP has an internal volume of 33.2 m³. In practice, plan for 25–28 CBM of usable loading space after accounting for packing inefficiency, void fill, and any pallet bases. Never assume 100% volumetric utilisation in a real loading scenario.

What is the difference between 40GP and 40HC?

Same length, same width — the 40HC (High Cube) is 30 cm taller internally (2.69 m vs 2.39 m). That adds roughly 8.8 m³ of usable volume, bringing the total from 67.6 to 76.4 m³. The 40HC costs marginally more and is the default choice for most shippers today because the premium is small relative to the extra space.

What does container utilisation percentage mean?

It's your total cargo CBM divided by the container's usable volume, as a percentage. 50 CBM in a 67.6 CBM 40GP = 74% utilisation. Aim for 85–90% for FCL to be cost-competitive with LCL alternatives.

How do I account for packing inefficiency?

Apply a 10–15% inefficiency buffer to your calculated CBM. Cartons don't stack perfectly — dunnage, irregular shapes, and pallet bases all eat into volumetric efficiency. If this tool shows 28 CBM, plan for a container with at least 31–33 CBM of usable space.

Should I use a 20ft or 40ft container?

Under 25 CBM and under 28,000 kg — 20GP. Over 25 CBM or consolidating multiple purchase orders — 40GP or 40HC. The 40ft containers offer a lower rate per CBM, but 20ft containers are simpler to fill and move through ports with less demurrage risk on short-transit routes.

What happens if my cargo exceeds the payload limit?

The container will be rejected or attract overweight surcharges and port authority penalties. Payload limits are enforced strictly. This calculator will flag a weight warning if your cargo weight input exceeds the container's maximum. Always cross-check total cargo weight before booking.