FAQ – RV Weights and What They Mean!

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What is GVW, GVWR, and GCWR?

GVW, GVWR, and GCWR are abbreviations for the three most common weights that all RV operators must become very familiar with:

  • GVW: Gross Vehicle Weight—actual weight of a single vehicle or RV.
  • GVWR: Gross Vehicle Weight Rating—maximum allowed weight of a single vehicle or RV.
  • GCWR: Gross Combination Weight Rating—maximum allowed weight of all connected vehicles.

For detailed explanation of these and other weights, see Understanding RV Weights.

How do I calculate GCW?

Gross Combination Weight (GCW) is the actual weight of the tow vehicle, towed vehicle(s), and everything in them. To calculate GCW, weigh each individual vehicle to get their Gross Vehicle Weight (GVW). Then, add up all GVW’s to get the GCW. If a large truck scale is available, the GCW can be determined with a single weighing by driving all connected vehicles on the scale.

How do I calculate GCWR?

Gross Combination Weight Rating (GCWR) is the maximum allowed weight of all connected vehicles, as established by the vehicle or RV manufacturer. Therefore, GCWR cannot be calculated by the vehicle operator.

For detailed explanation of this and other weights, see Understanding RV Weights.

How heavy a trailer can my vehicle tow?

The maximum trailer weight is the difference between the weight ratings and the actual weight of the tow vehicle. Each vehicle has manufacturer weight ratings such as GVWR, GCWR, and others. You must first weigh the tow vehicle and then determine how much weight remains for the trailer by subtracting the actual weight from the ratings. See our Tow Vehicle Sizing page for details.

Do I need a special license to drive an RV?

A great majority of RV’s can be driven with a regular driver’s license. However, some states require a special license for large RV’s. In rare cases a Commercial Driver’s License (CDL) is required—if you are told that you need a CDL, be sure to do more research because very few non-commercial RV’s fall into this category. If your RV meets one of the following criteria, check with your state for special driver’s license requirements:

  • Single vehicle or towable combination having a weight rating of 26,001 lbs. or more
  • Towing a trailer with a weight rating of 10,001 lbs. or more
  • Is longer than 45 feet
  • Towing two units (for example, towing a boat behind a trailer)

See RV Driver’s License Requirements for a summary of the fifty states.

Where can I learn the meaning of RV terms and jargon?

The RV industry, like any other, has its own set of terms and jargon. To help you learn the meaning of these terms, we compiled a Glossary of RV Terms and also sprinkled our web pages with special links that allow you to hover with your mouse for a brief definition or click on the link to go to the glossary. Here is an example of our special glossary link: toad

How much does water, fuel, and propane weigh?

One gallon of the following liquids weighs:

  • Fresh water: 8.3 lb (3.8 kg)
  • Gasoline: 6.1 lb (2.8 kg)
  • Diesel fuel: 7.3 lb (3.3 kg)
  • Propane: 4.2 lb (1.9 kg)


If you do further research on the Internet, you will find slightly different numbers quoted for the above fluids. This is because liquid weights vary with several factors, the primary ones being their exact chemical composition and temperature. After doing our own research, we have settled on the above numbers, which represent liquids in common RV use scenarios.

Our Liquid Weight Calculator gives results in pounds and kilograms for the above liquids.

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Andy Herrick is a blogging nerd, #8 Enneagram, wannabe bread baker, INTJ, RV industry professional, and small business entrepreneur. He can be found hanging out with his lovely wife and family, skiing, cycling, climbing, hiking, and convincing anyone who will listen why dogs aren’t really that great of pets. Also, he runs this website.

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