Use this RV fuel cost calculator to estimate what a trip will cost in gas or diesel. Pick your RV class, enter your miles, MPG, and price per gallon, and you get your total cost, your cost per mile, and the gallons you need in seconds. It works for a motorhome, a camper van, or a truck pulling a trailer, and for gas or diesel.
How to Use the Calculator
Choose your RV class, and the calculator suggests a typical MPG for it. Replace that number with your own if you know it, then enter your trip distance and the price per gallon, using either the slider or the price box.
Press Calculate to see your total fuel cost, cost per mile, and gallons. Treat the result as a solid baseline, because hills, wind, and speed will move your actual numbers a little.
The RV Fuel Cost Formula
The math takes two steps. Divide your trip miles by your MPG to get the gallons, then multiply the gallons by the price per gallon. For 600 miles at 8 MPG, you need 75 gallons, which costs $337.50 at an example price of $4.50 a gallon.
To compare two trips or two RVs, divide the total by the miles to get your cost per mile. That same trip costs about $0.56 a mile. The prices in these examples are round numbers, so check today’s price before you budget.
What MPG Should You Enter?
Typical figures run 6 to 10 MPG for a Class A, 14 to 18 for a Class B, 8 to 14 for a Class C, and 10 to 16 for a truck towing a travel trailer. Published figures vary by source, as RVshare and Cruise America show, so treat these as planning ranges.
For your own number, divide the miles between two fill-ups by the gallons you added, and average a few tanks. Our RV gas mileage guide shows how to track it.
How Much Does It Cost to Fill Up an RV?
Multiply your tank size by the price per gallon. RVshare lists tanks of about 70 to 150 gallons on a Class A, 25 to 55 on a Class C, and about 25 on a Class B. At $4.50 a gallon, a 40-gallon Class C tank costs $180, and a 100-gallon Class A tank costs $450.
Most trips need more than one fill-up. Multiply your MPG by your tank size to get the miles per tank, then divide your trip miles by that number to see how many fuel stops to plan.
Gas or Diesel?
Compare cost per mile, not price per gallon. Diesel rigs usually get better MPG but often pay more per gallon, so the cheaper fuel at the pump may not be cheaper on the road.
Divide each price by its MPG to compare. A gas RV at 8 MPG and $4.50 costs about $0.56 per mile, while a diesel RV at 10 MPG and $6.00 costs about $0.60. Run the calculator once for each fuel and compare the totals.
What Changes Your RV Fuel Cost?
Speed, towing, and weight move your MPG the most. The U.S. Department of Energy says aggressive driving can lower gas mileage by 15% to 30% at highway speeds. Most trucks and SUVs also lose 2 to 5 MPG when pulling a trailer, according to CamperSmarts.
Water adds weight too, at about 8.3 pounds per gallon. A full 40-gallon fresh tank adds roughly 330 pounds, and a tall, boxy RV also fights headwinds and steep climbs.
How to Save Money on RV Fuel
Slow down. CamperSmarts says most motorhomes and tow vehicles run best at 55 to 65 mph, and a few extra mph can noticeably cut your MPG. Cruise near 60 when the road allows, and the savings add up over a long trip, since speed is a cost you control.
Travel light. Carry only the water you need on driving days, and fill the tank when you arrive. Every extra pound makes the engine work a little harder.
Compare prices. Check a fuel app like GasBuddy before you fill up. RVshare points out that saving $0.10 a gallon on a 100-gallon fill is about $10.
Check your tires. Underinflated tires add rolling resistance and make the engine work harder. Our tire pressure guide shows how to find the right number.
Skip the idle. The Department of Energy says idling burns a quarter to a half gallon of fuel per hour. If you will be stopped for more than a minute, shut the engine off.
Your Next Step
Run your numbers with your own MPG, then try a lower speed or the other fuel type and compare the totals. To add campsites and food to your fuel bill, use our RV trip cost calculator next, since fuel is only one part of a trip budget.