You are here

The relationship between gallons used over a given distance and miles per gallon (mpg) is not linear. Thus, an increase in fuel economy by 5 mpg does not translate to a constant fuel savings amount. Trading a low-mpg car or truck for one with just slightly better mpg will save more fuel than trading a high-mpg car or truck for one that is even higher. For example, trading a truck that gets 10 mpg for a new one that gets 15 mpg will save 33 gallons of fuel for every 1,000 miles driven. In contrast, trading a 30 mpg car for a new car that gets 35 mpg will save 5 gallons of fuel for every 1,000 miles driven.

Fuel Use versus Fuel Economy
Graph of energy consumption by sector and energy source in 1982. See table below for more detailed information.

Note: Each category on the horizontal axis shows a five-mile per gallon improvement in fuel economy.
Source: U.S. Department of Energy and Environmental Protection Agency, Fuel Economy Guide.

Supporting Information

Fuel Use Versus Fuel Economy
Fuel Economy
(miles per gallon)
Gallons Per
1,000 Miles
Difference in Gallons
Used from One MPG
Category to the Next
5 200.0  
10 100.0 100.0
15 66.7 33.3
20 50.0 16.7
25 40.0 10.0
30 33.3 6.7
35 28.6 4.7
40 25.0 3.6
45 22.2 2.8
50 20.0 2.2
55 18.2 1.8
60 16.7 1.5
Source: U.S. Department of Energy and Environmental Protection Agency, Fuel Economy Guide.

Return to 2013 Facts of the Week