What Is OOG Cargo?

If your cargo fits inside a standard 40-foot high-cube, roughly 12.03 m long, 2.35 m wide, and 2.69 m tall internally, you are "in gauge" and you book like anyone else. Once any dimension pokes past the container's outer limits, you enter OOG territory. And the cost structure changes sharply.

OOG is short for "Out of Gauge." It means cargo that will not fit inside a regular container. A bulldozer blade, a 12-meter steel column, a generator set, a yacht on a cradle, all OOG. The gauge limit is the outer boundary of the container equipment: 2.44 m wide and either 2.59 m or 2.90 m tall for a standard or high-cube unit.

What Are the OOG Categories?

Carriers break OOG into three dimensions, and each one triggers separate surcharges:

• Over-width (OW). Cargo past the 2.44 m external width of the equipment. The most common OOG category. Wide industrial presses, large-diameter pipes, prefabricated bridge sections, all OW. Carriers publish tiered over-width surcharges by width range. For example, COSCO's transpacific tariff sets over-width surcharges starting at USD 4,000 for cargo under 2.90 m total width, rising to USD 6,000 for cargo between 3.35 m and 3.96 m on a 20-foot unit.
• Over-height (OH). Cargo rising above the top rail of the equipment. Wind turbine towers, tall reactor vessels, heavy transformers. Even a few centimeters above an open top's side rail triggers OH classification. Published over-height surcharges follow height tiers, roughly USD 3,000 for cargo up to 2.87 m total height and USD 3,500 for 2.90 m to 3.33 m.
• Over-length (OL). Cargo projecting past the ends of a flat rack or platform bed. Less common, usually from railway rails, long beams, or bridge segments. A 40-foot flat rack bed is roughly 12.03 m internally, beyond that, an OL surcharge applies.

The gotcha: most OOG shipments hit two categories at once. A large generator set on a flat rack might be 3 m wide AND 3 m tall. The carrier charges both surcharges, and they stack. A single 40-foot unit from Shanghai to Los Angeles with combined OH+OW can carry published surcharges of USD 8,000+ on top of base ocean freight, before terminal handling fees.

How Is OOG Cargo Shipped?

This is not like booking a standard container. A dry container booking can be confirmed online in minutes. An OOG booking needs 7 to 14 days of lead time at minimum. For complex project cargo with multiple OOG units, plan on a month or more.

Measure everything. Not the cargo alone, measure it mounted on the transport equipment with all dunnage, cradles, and blocking in place. A 3 cm error in declared width can mean the difference between cargo that loads and cargo that gets bumped. Carriers reject or surcharge cargo that arrives with dimensions different from the booking. Maersk publishes a USD 500 misdeclaration fee when tendered cargo does not match the booking description.

Pick the right equipment. Over-height but within width? Open top. Over-width? Flat rack. Both over-width AND over-height with extreme weight? Platform container. Equipment availability varies sharply by port. Flat racks are a small slice of the global container fleet, and booking one out of a secondary port can mean a two-week wait while a unit is repositioned.

Get stowage approval. The carrier's planner must confirm the OOG unit fits on the specific vessel, on the specific voyage. OOG units almost always go on deck in outboard positions, they do not fit in the below-deck cell guides. Each OOG unit restricts adjacent and above-deck loading. On a full vessel, your cargo can roll to the next sailing.

Verify port handling at both ends. The crane must lift the gross weight. The spreader must handle the width. The yard must have space to stage the OOG unit. For over-height cargo, check inland route clearances, bridges, power lines, tunnels, from factory to port and from discharge port to final site.

Submit a lashing plan. Every chain, wire rope, and web lashing must be specified by position, orientation, SWL rating, and tension. The IMO CSS Code sets the baseline; most carriers add stricter requirements. The plan must be approved before the carrier accepts the booking.

What Does OOG Actually Cost?

The starting point is the revenue ton: the carrier charges the greater of actual weight (in metric tonnes) or volumetric weight (in cubic meters, usually converted at 1 CBM = 1 revenue tonne for sea freight). Then dimensional surcharges are applied per oversized dimension, per side.

Published carrier tariffs show how this works in practice. One carrier's transpacific tariff lists over-width surcharges for 20-foot units from USD 4,000 to USD 6,000 depending on actual width, and over-height surcharges from USD 3,000 to USD 5,000. These stack. Terminal handling for OOG adds another layer, the Georgia Ports Authority tariff shows USD 579 for over-height only, up to USD 1,577 for combined over-width plus over-length per lift.

The "slot multiplier" concept is the simplest way to think about it: if your cargo blocks 1.5 container slots on deck, expect to pay roughly 1.5 times the base rate. If it blocks 2 slots, you pay double. The planning lead time also catches people out, try to book OOG three days before sailing and you will almost certainly miss the vessel.

Frequently Asked Questions

How is OOG cargo freight calculated?

OOG freight starts with a revenue-ton calculation: the carrier charges the greater of actual weight (metric tonnes) or volumetric weight (cubic meters, typically 1 CBM = 1 tonne for sea freight). Dimensional surcharges are then applied per oversized face, per side. Published carrier tariffs show over-width surcharges of USD 4,000 to USD 6,000 and over-height surcharges of USD 3,000 to USD 5,000 on transpacific routes for a single 20-foot unit. These stack: an over-width plus over-height unit pays both. Terminal handling fees add another USD 580 to USD 1,577 depending on the combination of OOG characteristics, per Georgia Ports Authority published rates. Because OOG pricing varies by carrier and trade, shippers must obtain specific OOG quotations for each shipment, standard tariff rates do not apply.

What is the difference between OOG and breakbulk cargo?

OOG cargo still rides on container equipment, a flat rack, open top, or platform, and sails on a container vessel on a liner schedule. Breakbulk cargo sails as individual pieces on a general cargo or multi-purpose vessel, without container equipment. OOG gets the reliability of a published container sailing schedule; breakbulk handles more extreme sizes and weights but with less frequent departures. The practical cutoff: OOG on a containership generally works for cargo up to roughly 40 tonnes with moderate overhang; breakbulk is the only option when cargo exceeds flat rack or platform weight limits, or for port pairs with no OOG-capable container service.

Related Terms

• Flat Rack Container, The primary OOG equipment: a flat bed with collapsible or fixed end walls, no side walls, no roof. Default choice for over-width cargo.
• Open Top Container, Full side walls and end walls but a removable roof. For over-height OOG that stays within container width.
• Breakbulk Cargo, Cargo shipped as individual pieces, not on container equipment. The alternative when OOG container shipping is not viable.