A warehouse ships the same goods every week in the same trucks. Then a new customer asks for its own pallet, or purchasing finds a cheaper supplier with a slightly different size, and from that week on the trucks leave with a gap down the middle that nobody can use. Nothing on the freight invoice changes. The number of trucks does.
The pallet is usually chosen by someone who never sees a truck being loaded. This article shows how to check, with a tape measure and ten minutes of arithmetic, what a pallet size does to every vehicle you pay for.
The one measurement that decides it: inside width
Pallets go into a truck in rows, usually two side by side. So the first question is not the pallet's area. It is whether two of them fit across the inside of the body, and how much width is left over.
Thai law puts a ceiling on that. Ministerial Regulation No. 60 of 2009, under the Land Transport Act, limits a goods vehicle to 2.55 metres wide, measured at the widest part of the body. A box body with refrigeration may be 2.60 metres. Those are outside measurements. Inside, you lose the thickness of both walls, and an insulated body loses more.
Published container dimensions show how much that is in practice:
| Deck | Inside width | Inside length |
|---|---|---|
| 20 ft dry container | 2,352 mm | 5,900 mm |
| 40 ft dry container | 2,352 mm | 12,032 mm |
| 40 ft refrigerated container | 2,290 mm | 11,599 mm |
A truck's own box body is built to its maker's drawing, so there is no standard figure. The only reliable number is the one you measure. But the arithmetic below works the same way for any deck.
What each pallet size needs across the deck
ISO 6780 recognises six pallet sizes. Here is the width each needs for two pallets side by side, and what is left over in a dry container (2,352 mm) and a refrigerated one (2,290 mm):
| Pallet (mm) | Two across, as placed | Width needed | Spare, dry | Spare, reefer |
|---|---|---|---|---|
| 1,100 x 1,100 | 1,100 + 1,100 | 2,200 | 152 | 90 |
| 1,140 x 1,140 | 1,140 + 1,140 | 2,280 | 72 | 10 |
| 1,067 x 1,067 | 1,067 + 1,067 | 2,134 | 218 | 156 |
| 1,200 x 1,000 | 1,200 + 1,000 (one turned) | 2,200 | 152 | 90 |
| 1,200 x 1,000 | 1,200 + 1,200 | 2,400 | does not fit | does not fit |
| 1,200 x 800 | 1,200 + 800 (one turned) | 2,000 | 352 | 290 |
| 1,219 x 1,016 | 1,219 + 1,016 (one turned) | 2,235 | 117 | 55 |
Three things stand out.
- Two 1,200 mm edges side by side need 2,400 mm. That is wider than a container, and on a truck at the 2.55 m legal limit it only fits if each wall is under 75 mm thick. On many box bodies the 1,200 mm pallet cannot go two across that way at all.
- A 1,140 mm square pallet in a refrigerated box leaves 10 mm. ISO allows each pallet to be up to 3 mm oversize. On paper it fits. In practice no forklift driver can place two of them with 5 mm either side.
- Some sizes only fill the width by turning every other pallet. A row of one 1,200 x 1,000 pallet lengthways and one crossways uses 2,200 mm. That is a good fit, but the forklift has to pick up the turned pallet from its other side. That needs a four-way entry pallet, one the forks can enter from all four sides. With a two-way pallet the pattern often cannot be loaded.
Length works in steps, not smoothly
Once the width is settled, the length decides how many rows you get. Rows come in whole numbers, so a small difference in length can win or lose a whole row.
Take the 40 ft dry container, 12,032 mm inside. Ten rows of 1,100 mm pallets use 11,000 mm. An eleventh row would need 12,100 mm. The container is 68 mm too short for two more pallets. More than a metre of floor travels empty on every trip.
The same thing happens on trucks. Suppose one box body is 6,500 mm long inside and another is 6,600 mm. With 1,100 mm pallets, the first takes five rows (10 pallets) and the second takes six rows (12 pallets). A 100 mm longer body carries 20% more pallets. That is why "a six-wheeler" is not a capacity, and why truck classes are only a starting point.
Pallets per trip, worked out properly
Putting width and length together gives the most pallets one layer can hold. These counts use simple block layouts (each lane of pallets facing one way) and no gaps, so treat them as a ceiling. Real loading needs a little clearance.
| Pallet (mm) | 20 ft dry | 40 ft dry | 40 ft reefer |
|---|---|---|---|
| 1,100 x 1,100 | 10 | 20 | 20 |
| 1,200 x 1,000 | 9 | 22 | 20 |
| 1,200 x 800 | 11 | 25 | 23 |
| 1,067 x 1,067 | 10 | 22 | 20 |
Pallet count is the wrong way to compare them, because the pallets are different sizes. Compare the floor area carried, which is the number of pallets times the area of one:
| Pallet (mm) | 20 ft dry | 40 ft dry |
|---|---|---|
| 1,100 x 1,100 | 12.10 m² (87% of floor) | 24.20 m² (86%) |
| 1,200 x 1,000 | 10.80 m² (78%) | 26.40 m² (93%) |
The result reverses with the length of the box.
- In a 20 ft container, the 1,100 mm pallet carries 12% more goods per trip than the 1,200 x 1,000.
- In a 40 ft container, the 1,200 x 1,000 carries 9% more than the 1,100 mm pallet.
So there is no best pallet. There is only the best pallet for the vehicles you actually use. If most of your volume goes in one vehicle type, that vehicle should decide the pallet, not the other way round.
To put a price on it: goods that fill 100 forty-foot containers on 1,100 mm pallets would fill about 92 on 1,200 x 1,000 pallets, assuming the cartons sit equally well on both. That is eight trips in every hundred.
Height: the second layer
If the goods can take weight on top, a second layer doubles what the floor carries. Whether it fits comes down to one sum.
A standard container is 2,395 mm high inside, and the door opening is 2,292 mm. Two loaded pallets built to 1,200 mm each come to 2,400 mm. That is 5 mm too tall, so the second layer is lost completely. Build each pallet to around 1,100 mm instead and two layers fit, with room for the forklift to lift the top one into place.
This is the cheapest fix of all. It changes nothing about the pallet, only the number of carton layers the warehouse stacks on it. It only works for goods that can be stacked. If they cannot, they use their full floor area however short they are, as covered in what a carrier needs from you before it can quote.
Overhang: the width you forgot to count
Cartons often stick out past the pallet edge. That overhang counts towards the width as much as the pallet does.
Two 1,100 mm pallets with 30 mm of overhang on each side become two 1,160 mm loads, needing 2,320 mm. A dry container still takes them, with 32 mm to spare. A refrigerated container, at 2,290 mm, does not. The pallet size is the same. What changed is how the cartons were stacked.
Overhang also causes damage. The cartons rubbing along the wall as the load goes in are the ones sticking out. So when you measure, measure the loaded pallet, not the empty one.
Why changing the pallet is a bigger decision than it looks
A pallet size touches everything: the carton pattern, the racking beams, the dock equipment, and what your customers' warehouses will accept. A classic textbook case makes the point. A company dropped a toy's cardboard box to save packaging cost, found the toys could no longer be stacked on a pallet, and had to add a second kind of load unit. That cost more in storage and transport than the packaging had saved.
So work in this order, and stop as soon as the numbers are good enough:
- Change the build height so a second layer fits, if the goods can be stacked.
- Remove overhang by changing the carton pattern.
- Change the loading pattern, including turned pallets, if your pallets are four-way entry.
- Change the vehicle to one whose inside dimensions suit the pallet you already have.
- Change the pallet only when the first four cannot close the gap, and after checking racking and customers.
What to do this week
- Measure the inside of every vehicle type you use. Width at the narrowest point, length and height, and the door opening. Ask your transportation company for the inside dimensions in writing, not the vehicle class.
- Measure your loaded pallets, including overhang and build height, for your five highest-volume products.
- Work out one layer: how many fit across, how many rows fit along, and whether a second layer fits under the roof and through the door.
- Convert to floor area carried and to cost per pallet (the trip price divided by the pallets that fit). Do the same for one alternative: a different build height, a turned pattern or a different body.
- Put the answer in your quote requests. A carrier that knows your loaded pallet size and count can pick the vehicle that fits it, instead of guessing and sending one that leaves the middle empty.
The one sentence to remember
A pallet is not "standard" until you have checked that two of them, fully loaded, fit side by side inside the vehicles you actually hire. That one check decides how much of every truck you pay for and leave empty.