How Much Will Fuel Cost on Your RV Trip?

RV fuel cost depends on the RV, its weight, the terrain, speed and wind, so any single “average” number can be far off for your trip. That’s why we don’t publish an MPG figure here. Instead, here’s how to estimate your own cost and tighten the estimate as you drive.

What is the formula?

Fuel cost = miles ÷ MPG × price per gallon.

Worked example with made-up round numbers (not a real RV’s rating): a 600-mile round trip, an RV you’ve logged at 10 MPG, and fuel at $4.00 a gallon. 600 ÷ 10 = 60 gallons; 60 × $4.00 = $240. Swap in your own numbers.

How do you use the DOE/EPA trip calculator?

The Fuel Economy Trip Calculator at fueleconomy.gov is run by Oak Ridge National Laboratory for the U.S. Department of Energy and the U.S. Environmental Protection Agency. It works in two steps:

1. Select vehicles. The page says you can edit vehicles to personalize the MPG and fuel prices. If your RV isn’t listed, pick a vehicle and set the MPG to your own figure.
2. Enter the trip: starting point, stops and destination. You can drag the route line on the map, and the trip fuel cost updates.

For a towable, use the MPG of your tow vehicle while towing, which is usually lower than its unloaded rating.

Where do you get the fuel price?

The U.S. Energy Information Administration publishes weekly average retail gasoline and diesel prices by region at eia.gov. Check whether your RV uses gasoline or diesel, and use the region you’ll drive through.

How do you find your RV’s real MPG?

1. Fill the tank and write down the odometer reading.
2. Drive normally.
3. At the next fill-up, fill again and note the gallons added and the new odometer reading.
4. MPG = miles driven ÷ gallons added. Average several fill-ups, and log towing and mountain trips separately.

Renting? Ask the owner or rental company for their own logged MPG, and check the rental agreement for mileage charges, which are separate from fuel.

What other trip costs should you add?

Campsite fees, propane refills, dump-station fees, generator-hour charges (on some rentals) and tolls. Our first-rental checklist lists what to ask, and rent or buy covers the bigger picture.

How do you compare two routes?

Run the trip calculator once for each route with the same MPG and fuel price, and compare the totals. A shorter route with steep grades or heavy traffic can use more fuel per mile than a longer flat one, so log real fill-ups on similar roads if you can. Also check that each route fits your RV’s height and length, and that campgrounds along the way have sites for it.

How much buffer should you add?

We don’t publish a standard buffer, because it depends on your RV, load, weather and route. Instead, run the calculator with your average MPG and again with your worst logged MPG (for example, from a towing or mountain trip). Budget the higher number. If fuel prices are moving, check the latest EIA weekly price before you leave.

What does a simple trip worksheet look like?

1. Total miles from the trip calculator.
2. Your logged MPG, average and worst.
3. Fuel price from EIA for your region and fuel type.
4. Fuel cost at average and worst MPG.
5. Campsite fees from each booking.
6. Propane, dump-station and toll estimates.
7. Rental mileage and generator charges, if any.

What are the common mistakes?

• Using a car’s MPG for an RV, or an unloaded rating for a tow vehicle while towing.
• Using gasoline prices for a diesel RV.
• Forgetting rental mileage charges, which are separate from fuel.

How can you use less fuel?

Practical steps that don’t need special products: keep tires at the pressure on the vehicle’s label (see our tire guide), drive at a steady speed, carry only the water and gear you need on travel days, and plan fewer, longer stays instead of moving every day. Track your own MPG before and after any change so you know whether it helped on your RV.

What should you do after the trip?

Compare your estimate with what you actually spent on fuel, and update your logged MPG with the new fill-ups. Note the route, the load, the weather and whether you were towing. After a few trips you’ll have your own numbers for similar routes, which beat any general estimate.