Fuel is usually the single biggest variable cost of RV travel, and it’s the one most likely to blow a trip budget. The calculator below estimates what a trip will cost using the current national average price for gas and diesel — then lets you adjust the price for your local pumps and your rig’s real-world mileage.

What MPG should you expect?

Fuel economy varies enormously by RV class, so use a number that matches your rig rather than a generic guess:

• Class A motorhomes: typically 6–10 MPG (gas) or 8–13 MPG (diesel pushers). The big diesel coaches get better mileage but burn pricier fuel.
• Class C motorhomes: usually 8–13 MPG depending on size and engine.
• Class B camper vans: the mileage champs at 16–22 MPG, often diesel or efficient gas V6s.
• Travel trailers & fifth wheels: you’re really measuring your tow vehicle — expect a 25–45% drop from its unloaded MPG once you’re hitched up. A truck that gets 20 MPG empty may see 12–14 towing.

Why the price field matters

The national average is a useful starting point, but pump prices swing by region and season. The West Coast routinely runs $0.50–$1.50 above the national average, while Gulf Coast states often sit below it. Diesel and gas also diverge — diesel usually costs more per gallon but the better mileage of a diesel rig can still come out ahead on long hauls. For an accurate estimate, drop in the price you’re actually seeing on your route.

Simple ways to cut RV fuel costs

• Slow down. Aerodynamic drag climbs sharply above 60 mph; dropping from 65 to 60 can add 1–2 MPG on a big rig.
• Keep tires at spec. Underinflated RV tires waste fuel and are a blowout risk — check them cold before every leg.
• Lighten the load. Travel with empty holding tanks and skip hauling a full fresh-water tank unless you’ll boondock.
• Plan fuel stops. Apps that show diesel prices along your route can save real money on a cross-country trip.

National average prices shown above are sourced from the U.S. Energy Information Administration and refresh weekly. This tool is for planning estimates only — your actual cost depends on terrain, weather, driving style, and local prices.