How many cartons fit in a container? Real counts for 20ft, 40ft and 40HQ

The honest answer is "it depends on the carton" — but that's not useful when a customer is waiting. This page gives you the working counts by carton size, tells you when to trust them, and shows why the same cargo can come out 20% apart.

1. The container numbers you're working from

Every carton count starts with container internal dimensions — not the external ones printed on the side of the box. Customs, tariffs and shipping quotes refer to the inside, because that's the space your cargo can occupy.

Two things to notice. First, the 40HQ is the same length and width as the 40GP — only the height changes, by about 30 cm. Second, the gap between "nominal" and "realistic" is not a rounding error; it's 10–15% of the container, and it exists because of how cargo fits.

2. Carton counts by size

The table below takes common carton sizes and shows what fits, using realistic loading efficiency (roughly 85–90% of nominal for well-matched cartons). Treat them as a planning starting point, not a promise.

3. Why the same carton gives you two different answers

Picture a 60 × 40 × 40 cm carton in a 40HQ, whose internal width is 235 cm. Lay the carton with its 60 cm side across the width and you fit 3 across (180 cm), leaving 55 cm of dead space. Rotate it so the 40 cm side runs across the width and you fit 5 across (200 cm), leaving 35 cm. Same carton. Different answer.

That's the whole game. Volume division pretends cargo pours into the container like liquid. Real cartons are rigid and have to be arranged, and each arrangement wastes a different amount of space.

Between the top and bottom rows there is a 200+ carton swing — on the same cargo, in the same container, with the same dimensions. That spread is the entire reason a loading calculator exists.

4. What also eats into your carton count

Weight, not volume, may be your real ceiling

If your cartons are dense, the container will hit its payload limit before it runs out of space. A 40HQ payload is 26,500 kg. If each carton weighs 25 kg, you can only load 1,060 of them — and if they're small, that might be well short of the volume limit. Check density against the container's break-even point (347 kg/m³ for a 40HQ) before you count anything.

Palletising

Goods on pallets occupy 30–50% more volume than the same goods loose, because the pallet itself and the gaps between pallets are billable. A carton so large that only a few fit per pallet can lose even more. If stacking is possible, loose loading almost always carries more.

Non-stackable cargo

Anything marked "this way up" or that can't bear weight on top effectively has the container's full height to itself. That is often a 30–50% volume penalty, and no layout trick recovers it. This is exactly the case where an explicit "no-flip" or single-layer calculation saves you from a nasty surprise at the loading dock.

The door and the last metre

The load has to get in through the door, and the last 30–50 cm of a container is usually kept clear for securing. Small allowances, but they accumulate.

5. Getting your actual number instead of an estimate

Every number on this page is a reference. Your real answer depends on your carton's exact dimensions, its weight, and whether it stacks. The reliable route is to calculate the layout rather than divide volumes:

1. Enter each carton's length, width and height in centimetres.
2. Add the quantity you need to ship and the weight per unit.
3. Choose the container type (20GP, 40GP, 40HQ, 45HQ).
4. Set stacking rules — mixed, unstackable, or zoned.

A 3D loading calculation tries the orientations, works out how many units fit, reports the loading efficiency and the weight used, and draws a loading plan you can hand to the warehouse. It takes about a minute per scenario and eliminates the "we're a dozen cartons short" conversation entirely.

6. Frequently asked questions

How many cartons fit in a 20ft container?

A 20GP has 33.2 m³ nominal and 28–31 m³ realistic. For a 60 × 40 × 40 cm carton that's roughly 290–320 on paper, falling to about 245–280 in practice once layout and securing space are accounted for.

How many cartons fit in a 40ft container?

A 40GP holds 67.7 m³ nominal (57–63 m³ realistic), so roughly 500–570 of the same carton. A 40HQ holds 76.3 m³ nominal (64–71 m³ realistic), giving about 570–640.

Is a 40HQ worth it over a 40GP?

If your cargo stacks, yes — the extra 30 cm of interior height is about 12.7% more volume for typically a modest price difference. If your cargo can't be stacked, the 40HQ buys you nothing, because the limit isn't volume.

Why does the same carton give different counts?

Because fitting depends on how dimensions divide into the container, not on volume. Rotating a carton can turn a wasted 55 cm strip into a wasted 35 cm, changing the count. Layout alone typically swings the result by 15–25%.

Should I add a buffer before quoting a customer?

Always. Take the calculated figure and subtract 5–10% before you commit. Cartons get slightly squashed or bulged, loading crews don't optimise, and the last row rarely goes in perfectly. A buffer is cheaper than a second shipment.

How do I find the exact number for my cartons?

Use the Container Loading Calculator: enter dimensions, quantity and weight, pick the container, and it returns the fitted quantity, loading efficiency and a 3D loading plan. Free and browser-based.