| Class | Approx. capacity | Limiting constraint |
|---|---|---|
| Feeder | up to ~3,000 TEU | Regional port depth and crane reach |
| Panamax | ~3,000 – 5,100 TEU | The original Panama Canal locks: 32.3 m beam |
| Post-Panamax | ~5,100 – 10,000 TEU | Too wide for the original locks |
| Neopanamax | ~10,000 – 14,500 TEU | The expanded Panama Canal locks: 51.25 m beam, 366 m length |
| Ultra Large Container Vessel | 14,500 and above TEU | Berth depth, crane outreach, and the Suez Canal |
Feeder
up to ~3,000 TEU
Moves boxes between a hub and the smaller ports the big ships never call at. Often geared — carrying its own cranes — so it can work ports without shoreside equipment.
Panamax
~3,000 – 5,100 TEU
Sized to the century-old locks. The 2016 expansion made the class largely historic, but the beam limit still shapes older tonnage and some port infrastructure.
Post-Panamax
~5,100 – 10,000 TEU
The first generation built to ignore the old canal, trading flexibility for economies of scale on the main east–west lanes.
Neopanamax
~10,000 – 14,500 TEU
Built to the maximum the expanded canal accepts. The reason the expansion mattered commercially: it reopened the US East Coast to ships of this size.
Ultra Large Container Vessel
14,500 and above TEU
Confined to the highest-volume lanes because only a handful of ports can work them. Cannot transit Panama at any size; Suez or the Cape are the options.
Questions
- What does Panamax actually mean?
- A ship sized to the original Panama Canal locks, whose 32.3 m width set the beam limit. The 2016 expansion introduced the larger Neopanamax dimensions, so the original class is now largely historic.
- Why can the largest ships only call at a few ports?
- Berth depth and crane outreach. A ship twenty-four containers wide needs cranes that can reach across it and water deep enough to float it loaded, and comparatively few terminals have both.
- Are these classes an official standard?
- No. They are commercial conventions and the boundaries between them are approximate. The constraints behind them are real, though — a Panamax is defined by a lock, not by a category.
Provided for convenience and general information only.Figures, definitions and descriptions on these pages are compiled from publicly available sources — published industry standards, official code registers and carriers' own published specifications — and are nominal: actual equipment, regulations and commercial terms vary by manufacturer, carrier, jurisdiction and contract, and change over time. FrateZone is not the issuing authority for any of it, does not warrant that any figure here is correct, current or complete, and makes no representation that a source has not changed since it was read. Where a specification belongs to a specific physical unit or a specific contract — a container's certified plate, an airline's tariff, the wording of your own sale agreement — that document governs, not this page. FrateZone accepts no liability for any error or omission here, nor for any operational, commercial, financial or legal decision taken in reliance on it. Verify against the authoritative source before you act.