The cargo size determines the dimensions of the semi-trailer needed to haul it.
Some types of semi-trailer have the ability to change their size configuration in such a way that they can haul freight of a wide range of sizes.
While the standard width of the semi-trailer may vary slightly, the length of some types of semi-trailers may change significantly.
That feature allows them to load larger freight on it.
Below check out the dimensions of different types of semi-trailers.
1. 48 ft and 53 ft semi-trailers

The US Department of Transportation set the standards for semi-trailer dimensions that can legally use the highways across the country.
If the cargo exceeds these max standards for 53-foot trailers, the driver needs additional permits to legally transport the oversized load.
Due to their enclosed nature, semi-trailers, also known as dry vans, transport the most versatile type of products.
This characteristic of the dry vans protects the freight from being damaged by external elements like rain, dust, or wind.
Standard semi-trailer dimensions | |
Length | 48'-53' |
Width | 102" |
Door height | 110" |
Total height | 13'6" |
Door types | Swing /Roller doors |
Semi-trailer inside cargo capacity | |
Cargo width | 98"-101" |
Cargo height | 108"-110" |
Cargo weight | 45,000 lbs |
Pallet count | 24-26 |
2. Flatbed semi-trailers

Flatbed semi-trailers can transport long or heavy freight that don't fit into an enclosed trailer.
The open nature of the flatbed trailer allows the shipper to load or unload the freight from the rear, sides, or from the top.
Flatbeds are loaded or unloaded from the ground rather than from the dock.
Flatbed semi-trailer dimensions | |
Length | 48'-53' |
Width | 102" |
Height | 60" |
Flatbed semi-trailer capacity | |
Cargo width | 102" |
Cargo height | 102" - 108" |
Cargo weight | 48,000 lbs |
Pallet count | 24 |
3. Reefer semi-trailers

During the entire transit time, reefer semi-trailers have the ability to maintain a specific temperature range inside the trailer.
Because of that, reefers transport temperature-sensitive products. These products require specific temperature ranges to arrive safely to the delivery.
Otherwise, the product arrives altered and unsafe to use.
Reefer semi-trailer dimensions | |
Length | 48'- 53' |
Width | 102" |
Door height | 110" |
Height | 13'6" |
Reefer semi-trailer inside cargo capacity | |
Cargo width | 96" - 98" |
Cargo height | 102" |
Cargo weight | 44,000 lbs |
Pallet count | 24 |
4. Step-deck semi-trailer

Step-deck semi-trailers transport products that are too tall for a standard flatbed.
The trailer consists of two decks - the upper and the lower.
The use of the lower deck, or well, allows for freight up to 10’ high to be legally transported while still providing the same loading/unloading capabilities of a standard flatbed.
Step-deck semi-trailer dimensions | |
Length: Total | 48'- 53' |
Length: Lower deck | 37' - 43' |
Length: Upper deck | 10' - 11' |
Width | 102" |
Height: Lower deck | 42" |
Height: Upper deck | 60" |
Step-deck semi-trailer capacity | |
Cargo width | 102" |
Cargo height | 120" - 126" |
Cargo weight | 45,000 lbs |
Pallet count | 24 |
5. Double drop semi-trailer (Lowboy)

The double drop semi-trailers transport oversize freight.
The low profile of the well provides the ability to legally transport 12' tall freight.
Lowboy semi-trailer capacity | |
Length: Total | 48" |
Length: Main well | 26' - 30' |
Length: Front/Rear decks | 8' - 10' |
Width | 102" |
Height | 18" - 24" |
Lowboy semi-trailer capacity | |
Cargo width | 102" |
Cargo height | 144" - 150" |
Cargo weight | 40,000 lbs |
6. Conestoga semi-trailers

Conestoga semi-trailers provide the enclosed option of a dry vans while providing the same loading/unloading capabilities as a flatbeds.
When open, a sliding curtain provides the ability to load or unload freight from the side, rear, or top.
When closed, the curtain offers protection to the freight from weather.
Conestoga semi-trailer dimensions | |
Length | 48' - 53' |
Width | 102" |
Door height | 98" - 102" |
Total height | 13'6" |
Conestoga semi-trailer inside cargo capacity | |
Cargo width | 102" |
Cargo height | 98" - 102" |
Cargo weight | 45,000 - 48,000 lbs |
Pallet count | 24-26 |
7. RGN semi-trailers

RGN (removable gooseneck, also called low boy or double drop) semi-trailers transport oversize freight.
RGNs transport heavy machinery like tractors, specialty vehicles, and others.
With the ability to detach from the cab, and with drop-down ramps, freight can easily be driven on and off.
RGN semi-trailer dimensions | |
Length: Total | 48' |
Length: Main well | 26'-30' |
Length: Rear deck | 8' - 10' |
Width | 102" |
Height | 18" - 24" |
RGN semi-trailer capacity | |
Cargo width | 102" |
Cargo height | 144" - 150" |
Cargo weight | 40,000 |