DG, OOG, Reefer and Overweight labels often appear only after a basic freight rate has been requested. When the cargo data is incomplete, the first quotation may exclude carrier approval, special equipment, power supply, monitoring, lifting, lashing or inland permits. The result is not merely a higher budget: the booking may be rejected, rolled to another sailing, changed to a different container type or charged at the terminal after the cargo is ready. This article separates the pricing logic for each surcharge group, identifies the usual charging party and unit, lists the RFQ data required, and explains how to compare quotations on an equivalent scope. The objective is to distinguish transport charges from equipment, handling and compliance costs, and to identify items that can only be confirmed after the carrier has reviewed the technical cargo file.

Operational reference for importers, exporters, procurement, logistics and operations teams.

QUICK FACTS

Safety and compliance premium

Triggered by dangerous goods classification; driven by UN Number, Class, Packing Group where applicable, route and acceptance conditions.

OOG

Space and special-handling premium

Triggered when cargo exceeds the operating dimensions of the equipment; commonly involves Flat Rack/Open Top, lashing and special lifting.

REEFER

Cold-chain premium

Covers refrigerated equipment, PTI, power, monitoring, genset and temperature/humidity/ventilation requirements.

OVERWEIGHT

Weight-related premium

Triggered by commercial or operational weight thresholds on a transport leg; it is not the same as OOG.

SCOPE OF APPLICATION

This article supports RFQ preparation and quotation comparison for special cargo in ocean, air and associated inland transport. The OOG, Reefer and Overweight sections focus mainly on containerised transport, while DG principles apply to both ocean and air cargo.

Relevant to import, export, project cargo, machinery, chemicals, batteries, food, pharmaceuticals and temperature-sensitive commodities.
It does not replace carrier/airline booking approval, terminal rules, road regulations or a shipment-specific quotation.
One shipment may fall under multiple categories, such as DG + Reefer or OOG + Overweight; surcharges and approvals may therefore accumulate.

KEY TERMS

Term	Meaning	Role in pricing
DG – Dangerous Goods	Cargo classified as hazardous under the rules applicable to the transport mode.	Determines acceptance, packing, marking, labelling, documentation and safety premiums.
UN Number / Class / Packing Group	UN identification number, hazard class and packing group where the packing group applies to the substance or article.	Core data for route restrictions, segregation and handling assessment.
SDS / MSDS	A safety data sheet describing composition, hazards, handling measures and transport information.	A preliminary review source; it does not by itself replace DG classification or carrier acceptance.
DGD – Dangerous Goods Declaration	The dangerous goods declaration prepared by the shipper as required for the relevant transport mode.	Used to verify classification, quantity, packaging, marks and declaration responsibility before carrier acceptance.
OOG – Out of Gauge	Cargo protruding beyond the operating dimensions of the selected container/equipment in length, width or height.	Drives lost-slot calculation, special equipment, lashing and lifting arrangements.
In-gauge special equipment	Cargo carried on Open Top/Flat Rack equipment while remaining within the equipment’s operating envelope.	May attract special-equipment pricing without the same OOG premium as protruding cargo.
Reefer	A refrigerated container or vehicle used to maintain controlled temperature conditions.	Triggers refrigerated equipment freight and PTI, plug-in/out, power, monitoring and genset costs.
PTI – Pre-Trip Inspection	Technical inspection of reefer machinery before release for stuffing.	Confirms operational readiness; it may be charged separately by the carrier, depot or terminal.
Overweight / Heavy cargo	Cargo or packed container exceeding a commercial or technical weight threshold on a transport leg.	May require heavy-weight surcharge, suitable chassis, permits, route survey or special lifting.
VGM – Verified Gross Mass	Verified total mass of a packed container.	Required before loading under SOLAS; it is different from the cargo net weight.

PRICING LOGIC AND OPERATING MECHANISM

1. DG: payment for safety, compliance and operational restrictions

A DG surcharge is more than a fee for applying hazard labels. The carrier must review classification, packing, quantity limits, stowage/segregation, transhipment ports and handling capability at origin and destination. Cargo with the same commercial name may receive a different acceptance decision or price because the UN Number, Class, applicable Packing Group, concentration or packaging is different.

2. OOG: payment for occupied space and special operations

OOG cargo may block adjacent or upper slots and may require Flat Rack/Open Top equipment, positioning, lashing, survey and special cranes. CBM alone is not a sufficient pricing basis; the carrier needs packed dimensions, directional overhang, centre of gravity and lifting details.

3. Reefer: payment for refrigeration equipment and condition control

Reefer pricing reflects specialised equipment, energy and monitoring. In addition to freight, quotations may separate PTI, plug-in/out, terminal electricity and monitoring, road genset, cold treatment or Controlled Atmosphere services. Set point is not the only data point: humidity, ventilation, pre-cooling and permitted temperature tolerance may also be required.

4. Overweight: payment for weight limitations across the chain

Overweight cargo can fit inside a standard container but exceed a carrier’s commercial threshold, terminal lifting limit or inland axle/road restriction. Costs may therefore arise from the ocean carrier, terminal, depot, trucking operator or permit process. Thresholds vary by trade, country, container type and transport plan.

Total special-cargo cost = Base freight + Cargo-type surcharge + Equipment/handling + Local charges + Inland/permits + Time-based incidentals

SURCHARGE COMPARISON

Cargo group	Trigger	Common charging basis	Typical charging party	Frequently omitted items
DG	Cargo is regulated as dangerous goods or requires a DG declaration.	Per shipment/AWB, container, DG type or route; some fees per document or handling event.	Airline/carrier, terminal, DG warehouse, packing/certification provider.	DG handling, documentation, segregated storage, inspection and transhipment charges.
OOG	Packed dimensions exceed equipment limits or require special equipment.	Per container/piece, over-width/height/length, lost slots and lifting plan.	Carrier, terminal, depot, lashing/survey provider and inland haulier.	Equipment positioning, lashing, survey, special lift, cradle, permits and escort.
Reefer	Cargo requires temperature/humidity/ventilation control or operating reefer equipment.	Per container/shipment, power/monitoring day, genset hour or control service.	Carrier/airline, terminal, depot, refrigerated haulier and monitoring provider.	PTI, plug-in/out, electricity, monitoring, genset, cold treatment and cleaning.
Overweight	Gross weight exceeds a commercial or technical threshold on a transport leg.	Per container/truck/piece, excess tonnage, trip, permit or lifting unit.	Carrier, terminal, haulier, permit and route-survey provider.	Heavy chassis, axle surcharge, route survey, bridge restriction, special lift and permit.

DOCUMENTS AND RFQ DATA

Required data	Typical owner	Used to assess	Risk if missing or wrong
Technical cargo name, use, composition and SDS/MSDS; UN Number, Class and Packing Group where applicable for DG.	Shipper/manufacturer; EHS or technical team.	DG classification, acceptance, packing and documentation.	Booking rejection, reclassification, extra charges or unsafe handling.
Final packed dimensions, directional overhang, piece weight, centre of gravity, lifting and lashing points.	Factory, packing contractor, project engineer.	Flat Rack/Open Top selection, slot loss, cranes, lashing and inland transport.	Incorrect OOG quote, unsuitable equipment, repacking or sailing change.
Net/gross weight, container tare, estimated and final VGM.	Shipper, stuffing warehouse, certified weighing party.	Payload, overweight threshold, terminal and road limitations.	No-load decision, reweighing, storage or alternative chassis/route.
Set point, commodity, humidity, ventilation, fresh-air exchange, pre-cooling, cold treatment/CA.	Cargo owner, QA, manufacturer, cold-chain specialist.	Reefer settings, equipment and monitoring services.	Cargo damage, temperature dispute or weakened claim evidence.
POL/POD, pickup/delivery addresses, ready date, required ETD/ETA, Incoterms and scope.	Procurement/logistics/forwarder.	Route restrictions, transhipment, permits and included/excluded items.	Comparison of unlike scopes, expired rate or missing origin/destination charges.

QUOTATION REQUEST AND REVIEW PROCESS

Classify the cargo correctly

Determine whether the shipment is DG, OOG, Reefer, Overweight or a combination. Do not request pricing with only a broad commercial name.

Complete the technical data pack

Finalise the SDS and DGD where applicable, packed dimensions, gross weight/VGM, lifting-lashing plan and temperature requirements before RFQ.

Request approval and scope-based pricing

Submit the file to the carrier/airline and inland haulier. Require clear inclusion, exclusion, unit, validity and cancellation/amendment conditions.

Compare the same transport scope

Separate at least five layers: freight, special-cargo surcharge, origin charges, destination charges and inland/permits. Do not compare port-to-port with door-to-door.

Lock the booking and instructions

Check the booking confirmation against container type, temperature, DG details, weight, dimensions, cut-offs and document deadlines.

Track actual costs

Monitor power days, storage, rollover, permit waiting, reweighing and special operations, then update the shipment’s landed cost.

RISKS AND COMMON ERRORS

Common error	Impact	Control measure
Declaring cargo as non-DG when it is regulated as DG, or providing inconsistent SDS data.	No-load decision, tariff/contract penalty, DG storage or safety exposure.	Validate classification with competent personnel and align SDS, DGD, marks, packaging and booking.
Providing product dimensions before pallet/cradle/packing.	Unexpected OOG, lost slots, unsuitable equipment and rework.	Measure final packed dimensions and state overhang in each direction.
Treating OOG and Overweight as the same issue.	Weight charges or dimensional charges remain unpriced.	Assess dimensions and gross weight/payload as two separate axes.
Reefer quotation contains only ocean freight.	PTI, power, monitoring, genset, cleaning or terminal daily fees appear later.	Require an included/excluded matrix and the start point for time-based charges.
Booking set point or ventilation differs from QA instructions.	Condition deviation and responsibility disputes during a claim.	Use one approved cold-chain instruction sheet and verify it before cut-off.
Late VGM or actual gross weight exceeds the accepted threshold.	Container is not loaded, must be reweighed, requires another chassis or delays delivery.	Use certified weighing, submit VGM before deadline and check full-route weight limits.

REGULATORY AND INDUSTRY SOURCES

Actual charges vary by carrier, trade, port, equipment, date and shipment file. The following official sources support the operating principles; reviewed on 17 July 2026.

IATA Dangerous Goods Regulations (DGR): classification, packing, marking, labelling and documentation for dangerous goods by air.
IMO – International Maritime Dangerous Goods Code: packaged dangerous goods requirements under SOLAS Chapter VII.
IMO – Verification of Gross Mass: methods and responsibility for verified gross mass before vessel loading.
Maersk – Out of Gauge Cargo: dimensional triggers and special-cargo handling.
Maersk – Reefer Containers: temperature, humidity and ventilation-control equipment.
Hapag-Lloyd – Ocean Tariff Rates and Surcharges: tariff lookup by trade, container type, commodity and date.

Regulatory note: road permits, axle limits, heavy/oversize cargo rules, port DG requirements and commodity controls must be checked for the actual country, route and shipment date.

FREQUENTLY ASKED QUESTIONS

Is the DG surcharge included in an “All-in” rate?

Only when the quote expressly includes the DG premium and related handling. “All-in” does not automatically include terminal, DG warehouse, inspection or misdeclaration costs.

Does Flat Rack cargo always qualify as OOG?

No. Cargo may use special equipment and remain in-gauge. The decisive point is whether the packed cargo protrudes beyond the operating envelope.

What is the difference between OOG and Overweight?

OOG is dimensional; Overweight is weight-related. A shipment may fall under either one or both.

Are reefer charges per container or per day?

Reefer freight is commonly per container/shipment, while power, monitoring, demurrage and some terminal services may be charged per day or operation.

Can the surcharge be quoted from CBM and total kilograms only?

Usually not for DG, OOG and Reefer. The carrier also needs DG classification, piece dimensions, overhang, centre of gravity, packaging and temperature parameters.

Who ultimately bears these charges?

The party invoiced by the carrier depends on the booking/service contract. The allocation between seller and buyer depends on the Incoterm and commercial agreement. The invoiced party and the contractual cost bearer are not always the same.

APPLICATION NOTE: This article explains quotation logic and controls; it is not a tariff. Confirm every amount against a valid quotation/tariff, booking approval and the technical file for the actual shipment.

ELECTRICAL – ELECTRONICS – IT EQUIPMENT

F&B

MACHINERY

HOUSEHOLD GOODS

COSMETICS – PERSONAL CARE