GVWR and GCWR: what the federal definitions say and where the CDL line falls
How the federal regulations define gross vehicle weight rating and gross combination weight rating, and how those two numbers set the commercial driver's licence groups for a truck and a trailer.
Checked against the sources at the bottom of this page on October 9, 2026. Rules, fees and pay change: the source has the last word.
This page reports what the official source says. It is not legal advice: ask the office named here. The text is from the Electronic Code of Federal Regulations, Title 49. It explains the terms and does not say which licence a particular driver needs.
The two definitions
Gross vehicle weight rating (GVWR) is a value the manufacturer specifies. The CDL rules in part 383 word it as the loaded weight of a single vehicle, and the carrier safety rules in part 390 word it as the maximum loaded weight of a single motor vehicle. It is a rating, not what the truck weighs on a given day. See eCFR 383.5 on CDL definitions and eCFR 390.5 on carrier safety definitions.
Gross combination weight rating (GCWR) is defined the same way in both parts, as the greater of two values:
- a value the manufacturer of the power unit specifies, if it is shown on the federal certification label; or
- the sum of the GVWRs or the actual gross vehicle weights of the power unit and the towed units, or any mix of the two, that gives the highest figure.
Both parts add an exception: the power unit's own GCWR is not used to define a commercial motor vehicle when it is not towing anything. Section 383.5 and section 390.5 also use the words gross vehicle weight and gross combination weight, meaning actual weight, in some definitions. They apply the test to whichever is greater, the rating or the actual weight.
Where the CDL line falls
Section 383.91 sets three commercial motor vehicle groups. The weight line it uses is 11,794 kilograms or 26,001 pounds, and a second line of 4,536 kilograms or 10,000 pounds for the towed unit.
| Group | How 383.91 words it |
|---|---|
| A, combination vehicle | Any combination with a GCWR of 26,001 pounds or more, provided the GVWR of the vehicle being towed is over 10,000 pounds |
| B, heavy straight vehicle | Any single vehicle with a GVWR of 26,001 pounds or more, or such a vehicle towing a vehicle of not more than 10,000 pounds GVWR |
| C, small vehicle | Any vehicle or combination that is neither A nor B, but is designed to carry 16 or more people including the driver, or is used to carry hazardous materials |
The section also says a driver who passed the tests for Group A may operate Group B or C vehicles with any required endorsements, and a Group B driver may operate Group C vehicles. See eCFR 383.91 on commercial motor vehicle groups.
Reading the wording against combinations
These readings only apply the section's words to combinations of ratings. They are not a statement about any real vehicle.
| Rating of the towing vehicle | GVWR of the towed unit | Result under the 383.91 wording |
|---|---|---|
| 26,001 pounds or more, alone | None | Group B |
| 26,001 pounds or more | 10,000 pounds or less | Group B |
| Combination GCWR of 26,001 pounds or more | Over 10,000 pounds | Group A |
| Under 26,001 pounds | 10,000 pounds or less | Neither A nor B |
The last row is Group C only if the vehicle carries 16 or more people or hazardous materials. Otherwise the section's three groups do not name it.
A second line at 10,001 pounds
Part 390 uses a different threshold for who counts as a commercial motor vehicle under the carrier safety rules. Its definition covers a self-propelled or towed vehicle used on a highway in interstate commerce to carry passengers or property when its GVWR or GCWR, or its actual gross weight or gross combination weight, whichever is greater, is 4,536 kilograms (10,001 pounds) or more. That line is part of the carrier safety definitions in part 390 and is a separate question from the CDL groups in part 383. The page on trucks and trailers for tree work lists how states word their own lines.