Standard Containers
LOP includes a built-in library of standard container types used across ocean freight, road transport, and air cargo. All dimensions in the library represent internal usable space — the actual clearance available for cargo after the container's structural elements are accounted for. External dimensions are not used anywhere in the optimizer.
ISO Shipping Containers
These are the four standard dry-freight container types used in international ocean shipping. All dimensions comply with ISO 668 and ISO 1496 specifications.
Specifications
| Type | Inner Length | Inner Width | Inner Height | Door Width | Door Height | Max Payload |
|---|---|---|---|---|---|---|
| 20' GP | 5,898 mm | 2,352 mm | 2,393 mm | 2,340 mm | 2,280 mm | 28,200 kg |
| 40' GP | 12,032 mm | 2,352 mm | 2,393 mm | 2,340 mm | 2,280 mm | 27,600 kg |
| 40' HC | 12,032 mm | 2,352 mm | 2,698 mm | 2,340 mm | 2,585 mm | 27,250 kg |
| 45' HC | 13,556 mm | 2,352 mm | 2,698 mm | 2,340 mm | 2,585 mm | 27,700 kg |
All dimensions shown are internal (usable space). The 40' High Cube is 305 mm taller than the standard 40' GP — a meaningful difference when loading tall pallets or machinery. If you are comparing options, the 40' HC is generally preferred over the 40' GP when cargo height is close to the 2,393 mm GP ceiling limit.
Choosing Between Container Types
20' GP — The most common container in global trade. Best suited for dense, heavy cargo where weight limits are reached before volume is full. Easier to position at inland depots and transfer terminals.
40' GP — Twice the floor space of a 20' GP at a lower cost-per-cubic-meter rate. The standard choice for lighter, bulkier cargo.
40' HC — Same footprint as the 40' GP but 305 mm taller. The preferred choice when loading standard EUR-pallets double-stacked, tall industrial equipment, or any cargo that approaches the standard GP ceiling.
45' HC — The largest standard ISO container. Offers the most cubic volume. Used for very large or particularly bulky shipments where maximizing a single container unit is important.
Not all ports and rail terminals accept 45' HC containers. Check with your carrier before choosing this type for a shipment that crosses multiple transport modes.
Trucks and Road Trailers
LOP supports road freight planning for common truck and trailer types used in North American and European markets.
North American Trailers
| Type | Inner Length | Inner Width | Inner Height | Max Payload |
|---|---|---|---|---|
| 53' Dry Van | 16,154 mm | 2,591 mm | 2,743 mm | 22,680 kg |
| 48' Dry Van | 14,630 mm | 2,591 mm | 2,743 mm | 22,680 kg |
European Trucks
| Type | Inner Length | Inner Width | Inner Height | Max Payload |
|---|---|---|---|---|
| Standard Curtainsider (13.6m) | 13,600 mm | 2,480 mm | 2,700 mm | 24,000 kg |
| Mega Trailer (13.6m) | 13,600 mm | 2,480 mm | 3,000 mm | 24,000 kg |
| Swap Body (7.45m) | 7,450 mm | 2,480 mm | 2,700 mm | 12,000 kg |
| Swap Body (7.82m) | 7,820 mm | 2,480 mm | 2,700 mm | 12,000 kg |
Truck containers in LOP support optional axle configuration data. When axle data is configured, LOP calculates front and rear axle load distribution and flags plans where weight distribution would cause a compliance issue under local road regulations.
Air Cargo Unit Load Devices (ULDs)
ULDs (Unit Load Devices) are standardized containers designed to fit aircraft cargo holds. Unlike sea containers, many ULD types are not rectangular — they have contoured (pentagonal or hexagonal) cross-section profiles that match the curvature of the aircraft fuselage.
LOP models these contoured profiles accurately in the 3D viewport and the solver respects the contour boundaries during optimization, ensuring items are not placed in the angled dead space.
Available ULD Types
| Type | IATA Code | Profile | Typical Aircraft |
|---|---|---|---|
| LD3 | AKE | Pentagon (1 angled side) | Wide-body lower deck |
| LD6 | ALF | Hexagon (2 angled sides) | Wide-body lower deck |
| LD7 88" | PAG | Rectangle (flat pallet) | Wide-body all decks |
| LD7 96" | PMC | Rectangle (flat pallet) | Wide-body all decks |
| LD8 | DQF | Pentagon | 767 lower deck |
| LD11 | ALP | Hexagon | Wide-body lower deck |
| LD1 | AKC | Pentagon | 747 lower deck |
| LD2 | DPN | Pentagon | 767 lower deck |
| M1 | AMJ | Hexagon | Main deck |
| LD3-45 | AKH | Pentagon (reduced height) | A320/321 |
| Half Pallet | PNA | Rectangle | Lower deck |
ULD Features in LOP
- Contoured 3D rendering — pentagon and hexagon cross-sections are clearly visible in the viewport, rendered with aluminum material appearance and metallic reflections
- Solver respects contour boundaries — items will not be placed in the angled dead space outside the usable volume
- Accurate weight limits — each ULD type enforces its IATA-certified maximum gross weight
Pentagon-profile ULDs (like LD3/AKE) have one angled side that reduces usable volume compared to a full rectangle. Hexagon-profile ULDs (like LD6/ALF) have two angled sides. LOP's solver accounts for these contours when calculating fill rates — the denominator is the actual usable volume, not the rectangular bounding box.
A Note on Internal vs. External Dimensions
All dimensions in LOP are internal — the clearance you can actually use for cargo. This is different from the external dimensions printed on container datasheet PDFs, which include the steel walls, floor panels, and roof corrugations.
Typical differences for a standard ISO container:
- External length is approximately 60–80 mm longer than internal
- External width is approximately 100–120 mm wider than internal
- External height is approximately 110–130 mm taller than internal
If you are working from manufacturer specification sheets and are unsure whether the stated dimensions are internal or external, always use the internal figures. When in doubt, measure the actual inside clearance before finalizing a container definition.
Door Dimensions
LOP tracks door width and door height separately from internal container dimensions. The door aperture is used to detect items that physically cannot enter the container through the door — regardless of whether they would fit inside once in.
If an item's cross-section is larger than the door opening, LOP will flag a hard constraint violation and prevent that placement. Check door clearance carefully when loading large machinery, oversized pallets, or items close to the door dimension limits.
Structural Elements
Real containers have physical structures that reduce the usable internal space. LOP models these accurately for sea containers, giving you realistic fill rate calculations.
What Is Modeled
Sea containers include the following structural elements in the 3D viewport:
- Corner posts — 178 × 160 mm steel posts at each of the four corners
- Top side rails — 60 mm intrusion from each side wall at the top
- Door header bar — structural beam above the door opening
- Corrugated walls — 25 mm wave depth on the right wall and back wall, simulating real container wall profiles
- Wood plank floor — textured floor surface
These elements are rendered in the 3D viewport with realistic materials and reduce the space available for item placement.
The Structure Toggle
A Structure toggle is located in the viewport left toolbar (box icon with/without an X mark):
- ON (default) — structural elements are visible in the 3D viewport and the solver respects them during optimization. Items will not be placed overlapping corner posts or intruding into top rail space.
- OFF — structural elements are hidden and the solver uses the full rectangular internal space. Useful for quick estimates or containers where structural elements are negligible.
Effect on Fill Rate
When Structure is ON, the fill percentage uses the usable volume (total internal volume minus structural element volume) as the denominator. This gives a more accurate fill rate that reflects real-world space constraints.
- Typical structural volume: approximately 3–4% of total container volume for standard sea containers
- With Structure OFF, the fill percentage is calculated against the full rectangular volume
Enabling Structure produces more realistic and accurate plans. For production load plans that will be executed by warehouse teams, we recommend keeping Structure ON. Turn it OFF only for rough feasibility checks or when using custom containers without modeled structural elements.
Next Steps
- Custom Containers — define vessels with non-standard dimensions
- Container Preferences — choose which types show up in your container picker
- Multi-Container Plans — add several containers to one plan