RV Fuel Cost Calculator

How much does it cost to drive an RV?

Miles divided by MPG, times the price, and the MPG is the number that moves. A motorhome getting 8 mpg costs twice as much per mile as a van getting 16, and a half-ton that gets 20 on its own gets nowhere near that with a trailer behind it. Per 1,000 miles, at an example $3.50 a gallon for gas and $4.00 for diesel:

Example prices only; use today's, which the EIA publishes as weekly US averages for gas and diesel. At the MPG's own speed; DEF at 2.5% of diesel burned.

What MPG does an RV get?

The published ranges, which are wide because weight, frontal area and speed dominate and every coach differs:

Dealer and rental figures from road use, with no common test behind them. The number to enter is your own, from the two-tank method below.

How much does towing a travel trailer reduce gas mileage?

In TFL's test, two F-150s towing 7,000 lb at 70 mph got 8.7 and 9.8 mpg. A drop of a third to a half is what owners commonly report, more for a tall trailer at highway speed and less for a low one at 55. Most of the loss is air: a travel trailer puts a wall the size of a garage door into the wind, and aerodynamic drag grows with the square of speed, which is why towing punishes speed even harder than driving solo does. Until you've measured yours, the tool plans at 60% of the truck's solo MPG, so a 20 mpg truck becomes 12 and a 1,000-mile trip goes from $175 solo to $292 towing. Whether the truck should be pulling that trailer at all is a separate check, and the towing-capacity calculator runs it.

Does driving slower save gas in an RV?

It saves more than in a car, and it's the one lever that costs nothing. The DOE's figures come from Oak Ridge National Laboratory's study of 74 vehicles: fuel economy is about 14% lower at 70 mph than at 60, and about 27% lower at 80. Fueleconomy.gov puts it more plainly: gas mileage "usually decreases rapidly at speeds above 50 mph." On a 1,000-mile trip in a rig that gets 10 mpg at 60, at $3.50 a gallon:

DOE Fact #982 (12.4% lower from 50 to 60 mph, 14% from 60 to 70, 15.4% from 70 to 80) and Fact of the Week #1240 (27% lower at 80 than at 60), from ORNL's 74-vehicle study; straight lines between the points, about 7% per 5 mph. Those are light-duty vehicles. A trailer's frontal area makes the penalty larger.

How far can I drive on a tank?

Range is figured to a quarter tank. That's the reserve that keeps a closed station or a headwind from stranding you, and on most motorhomes it's also where the generator's fuel pickup stops, so running below it means no generator either. Miles on a full tank down to a quarter:

75% of the tank at the MPG shown. A half-ton's 26–36 gal tank at towing MPG is often under 300 miles between fills, so look at the gaps in the route before you leave, especially in the West.

How much does a cross-country RV trip cost in fuel?

Coast to coast is roughly 2,800 miles, and the fuel bill spreads wider than the MPG does, because the smallest tanks stop most often. At a steady 62 mph and an example $3.50 a gallon:

One way, starting full; MPG at the speed it was measured. Fill-ups count only the ones on the road. The towing half-ton stops every 270 miles, which on some western stretches is closer to the gap between stations than you'd like.

Fuel is the biggest line on a long drive but not the only one: the trip cost calculator adds the campgrounds, food and tolls and sets the whole trip against the same nights by car and hotel.

Does running the generator while driving use the motorhome's fuel?

A motorhome's generator draws from the chassis tank, and on a hot travel day with the roof air running it's a sizable line on the bill. A 5,500 W gas generator at half load burns about 0.6 gallons an hour on the site's generator model; six hours of it is 3.8 gallons, the fuel for about 31 miles at 8 mpg. It also comes out of the same range, so the fuel stops above count it. On most motorhomes the generator's pickup stops at about a quarter tank, which is one more reason to treat the quarter as empty: below it you have neither range nor air conditioning. The generator page does the same arithmetic for your own generator, with its data-sheet figures.

Is a diesel RV cheaper to run than gas?

Only when its MPG advantage beats its price premium. Diesel commonly goes 20–35% farther on a gallon, and it usually costs more per gallon: at the example prices here, 14% more. So a diesel has to beat the gas rig's MPG by more than 14% just to break even on fuel, before the DEF it also burns (2.5% of diesel, a planning figure). A diesel coach at 12.5 mpg against a gas one at 10 spends $320 against $350 per 1,000 miles, plus about 2 gallons of DEF, a narrow win. At 11 mpg against 10 it spends $364 and loses. The diesel's bigger case is torque on grades, engine life and towing a car behind it. On fuel alone the two are close, and the result swings on the price gap at the pump, so enter today's prices for both.