How are Oil Tankers Classified by Size?
Oil tankers are essential to the global energy supply chain, transporting crude oil and refined petroleum products between production areas, refineries, storage terminals and consuming markets.
However, oil tankers vary significantly in size. Some are designed for short-distance coastal transportation, while others can carry millions of barrels of crude oil across oceans.
One of the most common ways to classify oil tankers is by deadweight tonnage (DWT). Based on their carrying capacity, tankers are generally grouped into categories such as Handysize, Panamax, Aframax, Suezmax, VLCC and ULCC.
Understanding these tanker size classes is useful not only for shipowners and operators, but also for ports and terminals that need to select suitable berths, loading facilities, mooring equipment and marine fender systems.
What does DWT Mean for an Oil Tanker?
DWT stands for deadweight tonnage.
It represents the total weight that a vessel can safely carry, including:
- Cargo
- Fuel
- Fresh water
- Ballast water
- Provisions
- Crew and other supplies
DWT should not be confused with the physical weight of the vessel itself.
For oil tankers, deadweight tonnage provides a practical indication of the ship’s cargo-carrying capacity and is widely used when comparing different tanker sizes.
The Average Freight Rate Assessment, or AFRA, system also classifies tankers primarily according to deadweight tonnage.
Main Oil Tanker Size Categories
1. Small and Coastal Tankers
Small oil tankers generally operate on short routes between coastal terminals, regional ports and nearby storage facilities.
Depending on the classification system, this group may include vessels below approximately 25,000 DWT.
Their relatively small dimensions offer several advantages:
- Access to smaller ports
- Lower draft requirements
- Greater flexibility for regional distribution
- Easier operation in restricted waterways
These vessels are commonly used for transporting refined petroleum products, bunker fuel and other liquid cargoes over relatively short distances.
2. Handysize Tankers
Handysize tankers are generally around 25,000 to 40,000 DWT, although some classification systems use slightly different ranges.
Their moderate dimensions allow them to operate at ports that cannot accommodate larger crude carriers.
Handysize tankers are often used for transporting:
- Diesel
- Gasoline
- Jet fuel
- Fuel oil
- Other refined petroleum products
Because of their flexibility, they are commonly found in regional and short- to medium-distance petroleum trades.
3. Handymax and Medium Range Tankers
Tankers in the approximately 40,000 to 55,000 DWT range are often described as Handymax or Medium Range, particularly MR2 product tankers.
These ships are widely used in the refined petroleum market.
Compared with smaller tankers, they offer greater cargo capacity while maintaining access to a relatively large number of ports.
This balance between capacity and port accessibility makes Medium Range tankers an important part of international petroleum product transportation.
4. Panamax and LR1 Tankers
Panamax or LR1 tankers generally fall within approximately 55,000 to 80,000 DWT.
The term “Panamax” originally referred to ships designed around the dimensional restrictions of the original Panama Canal locks.
In tanker markets, ships within this capacity range are commonly used for transporting petroleum products and, in some cases, crude oil.
Their larger cargo capacity allows them to operate efficiently on longer routes while still accessing many major petroleum terminals.
5. Aframax Tankers
Aframax is one of the best-known tanker size categories.
A typical Aframax tanker has a capacity of approximately: 80,000–120,000 DWT
The U.S. Energy Information Administration describes Aframax vessels within this range.
Interestingly, Aframax is widely used as a commercial vessel-size description but is not itself an official category within the traditional AFRA scale.
Aframax tankers are frequently used for crude oil transportation on short- and medium-distance routes.
They are particularly useful where ports or waterways cannot accommodate larger vessels such as Suezmax tankers or VLCCs.
Their combination of relatively high cargo capacity and good port accessibility makes Aframax vessels highly versatile.
6. Suezmax Tankers
Suezmax tankers typically fall within approximately: 120,000–200,000 DWT IMO studies have also used this range when categorizing Suezmax crude oil tankers.
As the name suggests, the Suezmax concept is associated with the approximate maximum vessel size capable of navigating the Suez Canal under relevant draft and dimensional restrictions. These ships are primarily used for transporting crude oil over long distances.
A typical Suezmax vessel provides substantially more cargo capacity than an Aframax while still maintaining greater route flexibility than some of the world’s largest crude carriers.
Suezmax tankers are therefore commonly used on major international crude oil routes.
7. VLCC – Very Large Crude Carrier
VLCC stands for Very Large Crude Carrier. VLCCs generally start at around 200,000 DWT, with many modern vessels having a capacity close to 300,000 DWT.
They are among the most important vessels in global crude oil transportation.
A VLCC can typically carry around 1.9 to 2.2 million barrels of crude oil, depending on the type and density of the cargo. VLCCs are especially suitable for long-distance, high-volume crude transportation. Typical trading routes may connect major crude-exporting regions with large refining markets in Asia, Europe and other parts of the world.
Because of their enormous dimensions, VLCCs require ports with:
- Deep navigation channels
- Large turning basins
- Suitable berth dimensions
- High-capacity mooring systems
- High-energy-absorption fender systems
In some locations where fully loaded VLCCs cannot directly enter a port, offshore loading, lightering or ship-to-ship transfer may be used instead.
8. ULCC – Ultra Large Crude Carrier
ULCC stands for Ultra Large Crude Carrier. These vessels represent the upper end of the oil tanker size range and are generally larger than conventional VLCCs.
Depending on the classification used, ULCCs may exceed approximately 320,000 DWT. Some ULCCs are capable of carrying several million barrels of crude oil. EIA notes that vessels in this category can carry approximately 2 million to 3.7 million barrels, depending on vessel size and cargo characteristics. Their enormous cargo capacity can provide excellent transportation efficiency on suitable routes. However, their size also creates operational limitations.
Only a limited number of terminals and waterways have sufficient:
- Water depth
- Channel width
- Turning space
- Berth strength
- Loading capacity
to accommodate these vessels safely. As a result, ULCCs are much less flexible than Aframax, Suezmax or many VLCC vessels.