When spot rates climb — as they did again in early July 2026 with Drewry's World Container Index above $4,500 per 40ft — the question is not just which carrier but which box. A 20ft container and a 40ft container carry different payload budgets, pallet counts, and all-in freight economics. Pick the wrong size and you either overpay per unit shipped or stuff a box so tight that weight limits bite at the gate.
This guide compares internal dimensions, typical pallet capacity, cost-per-unit math, and decision rules shippers use when booking FCL in a peak-season market.
Internal dimensions at a glance
| Spec | 20ft GP | 40ft GP | 40ft HC |
|---|---|---|---|
| Internal length | ~5.9 m (19'4") | ~12.0 m (39'5") | ~12.0 m |
| Internal width | ~2.35 m | ~2.35 m | ~2.35 m |
| Internal height | ~2.39 m | ~2.39 m | ~2.69 m |
| Door opening (W × H) | ~2.34 m × ~2.28 m | ~2.34 m × ~2.28 m | ~2.34 m × ~2.57 m |
| Typical max gross | 30,480 kg | 30,480 kg | 30,480 kg |
| Approx. payload | ~28,200 kg | ~26,500 kg | ~26,300 kg |
High-cube (HC) adds roughly 30 cm of height — valuable for light, bulky freight where cube fills before weight.
How many pallets fit?
Using standard EUR pallets (1200 × 800 mm) or US GMA pallets (48" × 40"), practical counts depend on pinwheeling, overhang rules, and aisle space for forklifts:
| Pallet type | 20ft GP | 40ft GP | 40ft HC |
|---|---|---|---|
| EUR (11 pallets) | 9–10 | 20–22 | 22–24 |
| US GMA (48×40) | 9–10 | 20–21 | 21–23 |
| Non-standard / mixed | 8–11 | 18–24 | 20–26 |
Double-stacking light cartons on pallets can raise piece count without changing pallet footprint — but only when crush limits and VGM allow.
Freight economics: when 40ft wins
Ocean carriers price 40ft boxes at a premium to 20ft, but rarely double. In peak markets, a 40ft might cost 60–80% more than a 20ft on the same lane — meaning cost per pallet often falls 20–35% when you fill the larger box.
Example (illustrative transpacific spot):
| Container | Spot rate (40ft equiv.) | Pallets loaded | Cost per pallet |
|---|---|---|---|
| 20ft | $4,000 | 10 | $400 |
| 40ft | $6,400 | 21 | ~$305 |
The 40ft wins on unit economics only if you use the cube. Shipping a 40ft at 50% utilization is usually worse than a full 20ft.
When 20ft is the better choice
1. Weight-heavy, cube-light cargo. Steel, machinery, dense beverages, or stone products may max payload before filling a 40ft. Two 20ft boxes can split weight across road-legal drayage limits.
2. Split consignees or staggered delivery. If half the order ships now and half in two weeks, a 20ft now + 20ft later can beat one under-filled 40ft.
3. Port or inland constraints. Some depots, rail ramps, or urban delivery routes handle 20ft more easily.
4. Inventory risk. High-value or seasonal SKU mixes may not justify committing an entire 40ft before sell-through is proven.
Decision checklist
Before you book, answer four questions:
- Will payload or cube bind first? Run weight and volume in the same model — Palletizr does both.
- What is cost per unit at 85%+ utilization for each container size on your lane quote?
- Does drayage allow gross mass for a fully loaded 40ft at origin and destination?
- Is peak-season front-loading pushing you to maximize one sailing — favoring 40ft if inventory supports it?
Bottom line
In a rising-rate environment, 40ft containers reward full loads with lower cost per pallet and lower cost per cubic metre. 20ft containers win when weight, split shipments, or partial inventory make a larger box wasteful. The cheapest container is the smallest size you can fill to target utilization without breaching VGM or road limits — not the one with the lowest headline rate.