About Container Loading Calculator
Container Loading Calculator is a one-file command-line tool for estimating how many flat-pack units, panels, or crates fit in 20ft and 40HQ containers. It compares volume and payload limits and reports which one constrains the load.
Key features
- 01Estimate units per layer and total load
- 02Compare volume and payload limits
- 03Cap stacking with a maximum layer option
- 04Try 90-degree unit rotation
Use cases
- 01Estimating flat-pack quantities before booking freight
- 02Checking whether a load is limited by volume or weight
Configuration
Remote servers need no local install. Pick your client, then copy the config or install in one click.
https://buildextechnology.com/api/mcpclaude mcp add --transport http cindyliao1106-container-loading https://buildextechnology.com/api/mcp{"mcpServers":{"cindyliao1106-container-loading":{"type":"http","url":"https://buildextechnology.com/api/mcp"}}}Open in Cursor{"servers":{"cindyliao1106-container-loading":{"type":"http","url":"https://buildextechnology.com/api/mcp"}}}Open in VS Code{"mcpServers":{"cindyliao1106-container-loading":{"type":"http","url":"https://buildextechnology.com/api/mcp"}}}{"mcpServers":{"cindyliao1106-container-loading":{"serverUrl":"https://buildextechnology.com/api/mcp"}}}Run commands in a terminal; paste JSON into the client’s MCP config and restart. Servers that need sign-in will prompt on first connect.
Tools
1| Parameter | Type | Required | Description |
|---|---|---|---|
| container | enum | Yes | Container type: 20gp (20ft general purpose) or 40hq (40ft high cube).20gp | 40hq |
| maxLayers | number | No | Optional stacking limit: the most layers you are willing to stack. Omit or send 0 for no cap. |
| unitWidthMm | number | Yes | Packed width of one unit, in millimetres. |
| unitHeightMm | number | Yes | Packed height of one unit, in millimetres. |
| unitLengthMm | number | Yes | Packed length of one unit, in millimetres. |
| unitWeightKg | number | Yes | Weight of one packed unit, in kilograms. |
| allowRotation | boolean | No | Optional. When true, the tool also tries each unit rotated 90 degrees and keeps the better units-per-layer. Default false, matching the web calculator. |
Details
From the project READMEContainer loading calculator
How many flat-pack units — or panels, or crates — fit in a 20ft or 40HQ container, and what limits the load: volume or payload. No dependencies, one file.
python3 container_loading.py 40hq 2900 2200 600 900
{
"container": "40ft high cube",
"units_per_layer": 4,
"layers": 4,
"units_by_volume": 16,
"units_by_payload": 31,
"units": 16,
"limited_by": "volume",
"volume_utilisation_pct": 80.2,
"payload_utilisation_pct": 50.3
}
The same unit in a 20ft, with a heavier unit, is weight-limited instead:
python3 container_loading.py 20gp 1000 1000 500 5000
# units_by_volume 40 · units_by_payload 5 · units 5 · limited_by "weight"
Options
| flag | what it does |
|---|---|
--max-layers N | caps the number of layers when the packing method limits stacking |
--rotate | tries rotating each unit 90° and uses whichever fits more per layer |
Why it refuses to calculate
If the packed length, width, height or the unit weight is missing, the tool raises an error listing exactly what is missing instead of returning a number. A guessed loading plan is how deposits get lost — the packed height and the unit weight are the two inputs that move the answer most, and both come from the factory packing method.
Container data used
Typical published internal dimensions and payloads. Confirm against the carrier's own data and the actual packing list before booking.
| container | internal L × W × H (mm) | payload (kg) |
|---|---|---|
| 20ft GP | 5898 × 2352 × 2393 | 28,200 |
| 40ft HQ | 12032 × 2352 × 2698 | 28,600 |
Volume utilisation is calculated on the packed envelope (length × width × height of one unit), not on the net product volume.
Web version
Same logic, in the browser, no install: container loading calculator — the tool we use ourselves when quoting flat-pack buildings and aluminium ceiling systems.
Tests
python3 tests/test_loading.py
License
MIT
Comments
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