A standard 40-foot refrigerated container holds 20 standard pallets (48 x 40 inches) in a single layer on the floor. That number assumes pallets are loaded with the 40-inch side facing the container walls, which is the most efficient arrangement given the interior width. The actual cargo you can fit depends on pallet height, weight, and the airflow clearances that keep a reefer functioning properly.
Why 20 Pallets Is the Standard Count
The usable interior of a 40-foot reefer is roughly 38 feet long and 7 feet 6 inches wide. That width accommodates two standard pallets side by side (each 40 inches wide), and the length fits 10 rows of pallets (each 48 inches deep). Two pallets across times 10 rows deep gives you 20 pallets total.
This is fewer than you’d fit in a standard 40-foot dry container, which has slightly more interior space. Reefer containers sacrifice a few inches of length, width, and height to insulation panels and the refrigeration unit mounted at one end. Those panels are what maintain temperature, but they eat into your loading area.
Internal Dimensions That Matter
A typical 40-foot high-cube reefer has internal dimensions of approximately 11,588 mm long (about 38 feet), 2,280 mm wide (about 7 feet 6 inches), and 2,537 mm tall (about 8 feet 4 inches). Exact measurements vary slightly between manufacturers. Hapag-Lloyd’s 40-foot reefer high cube, for example, lists an interior height of 2,425 mm (roughly 7 feet 11.5 inches), while SeaCube’s version measures 2,537 mm.
These differences matter if you’re stacking pallets high or loading oddly shaped cargo. Always confirm the specific container specs with your shipping line or container provider before finalizing your load plan.
Height Limits and Airflow Clearance
Fitting 20 pallets on the floor is only half the equation. How high you can stack cargo on each pallet determines your total volume, and reefer containers have stricter height rules than dry boxes.
Every reefer has a red line painted on the interior walls marking the maximum cargo height. You must keep all cargo below this line. The space above it allows warm return air to flow back to the refrigeration unit. Without that gap, the unit can’t circulate cold air effectively, and your cargo temperature will drift. As a general rule, leave at least 8 to 10 centimeters (roughly 3 to 4 inches) between the top of your cargo and the container ceiling.
Airflow doesn’t just run across the top. The container floor has a T-shaped channel design that directs cold air underneath and around the cargo. Pallets should sit flat on these floor channels without blocking them. You also want to avoid pressing boxes or shrink wrap directly against the side walls, since the corrugations in the insulation are designed to let cold air circulate around the outside of the cargo block.
Europallets Change the Math
If you’re shipping on Europallets (1,200 x 800 mm, or roughly 47 x 31.5 inches), the arrangement changes. Europallets are narrower than standard North American pallets, which means you can sometimes fit them in different configurations. However, the narrower width can also leave awkward gaps that reduce overall efficiency. Depending on orientation, you may fit a similar count or slightly more, but the cargo volume per pallet tends to be lower because of the smaller footprint. Run the specific dimensions against the container’s interior before assuming you’ll gain extra positions.
Weight Limits May Matter More Than Space
Dense cargo like frozen meat, seafood, or dairy can hit the container’s weight limit well before you run out of floor space. A 40-foot reefer high cube typically has a maximum gross weight (container plus cargo) of around 30,480 kg (about 67,200 pounds). The container itself weighs roughly 4,800 to 5,500 kg depending on the model, leaving you a payload capacity in the range of 25,000 to 27,000 kg (roughly 55,000 to 59,500 pounds).
Divide that by 20 pallets and each pallet can weigh about 1,250 to 1,350 kg (2,750 to 2,975 pounds) before you max out. For lightweight goods like flowers or pharmaceuticals, space is your constraint. For heavy frozen products, weight will be the bottleneck.
Tips for Maximizing Your Load
- Orient pallets correctly. Load the 40-inch side against the container walls so two pallets sit snugly across the width. Turning them the wrong way wastes space and can block airflow channels.
- Stack to the red line, not the ceiling. Filling every inch of vertical space will compromise cooling. Respect the marked maximum load height.
- Keep cargo away from walls. A small gap between the outer edges of your cargo and the container walls lets refrigerated air circulate properly on all sides.
- Pre-cool your cargo. Reefer units are designed to maintain temperature, not to bring warm cargo down to target. Loading cargo that’s already at the correct temperature protects your shipment and reduces strain on the unit.
- Check weight distribution. Unevenly loaded containers are a safety hazard during ocean transit. Spread heavy pallets across the floor rather than concentrating them at one end.
For most standard shipments, plan on 20 pallets per 40-foot reefer container. From there, your real planning work is making sure the height, weight, and airflow requirements all line up with what you’re actually shipping.