Fuel economy

Fuel economy is a measurement of fuel use. This measures how far a car can go using a set amount of fuel. Its units are miles per gallon—or for an electric vehicle, miles per gallon gasoline equivalent (MPGe). Sometimes, the term fuel efficiency is used. Its important to note that this is a colloquial term which is used in place of fuel economy.[1] Moreover, fuel economy may be confused with fuel consumption, however, these have different meanings—to learn more click here.

How to improve fuel economy

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It may not seem like it, but acceleration and speed during driving have a tremendous effect on fuel efficiency. Things like slowing down a little, not accelerating so rapidly substantially improve fuel efficiency. Also properly inflating tires to their proper pressure makes a big difference.

Savings based on fuel economy

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This is a table of fuel and carbon dioxide savings based on the fuel efficiency of the vehicle. Keep in mind that the make of the vehicle is not important here. Gasoline consumed is strictly how much gasoline is consumed, regardless of the type of car or truck it is.

MPG (US) Example km/L L/year kg CO2 produced Savings from 24mpg ($1.20/L) 5 year savings 10 year savings
18 Jeep Wrangler 7.58 2234 5,343 Costs an extra $668.40 -$3342 -$6,684
24 Toyota Camry V6 10.1 1677 4,011 0 0 0
30 Mini Cooper Clubman 12.63 1341 3,207 $403 $2,015 $4,030
38 Fiesta 3-cyl 16 1059 2,533 $741 $3705 $7,410
45 VW Golf TDI 18.95 894 2,403* $939.60 $4,698 $9,396
60 Kia Rio 1.1 CDRi 25.26 671 1,603 $1,208.40 $6,042 $12,084
73.5 VW Golf TDI Bluemotion [2] 30.94 547.6 1,309 $1,355.28 $6,776.40 $13,552.80
114** Nissan Leaf 48 --- 844 $1,588 $7,944 $15,888

*Diesel emits 2.7 kg CO2 per liter[3]


Fuel economy conversions

Figure 1.This is an example of the official label for a gasoline vehicle which outlines the fuel economy and consumption along with other information.

The metric system of discussing fuel economy is the same as the imperial system—the world has adopted the units of miles per gallon (see Figure 1). However, fuel consumption (a term sometimes confused with fuel economy) is measured in liters per hundred kilometers in the metric system. The unit converter below can help explore this difference between fuel consumption and fuel economy:

For Further Reading


  1. This is information obtained from speaking to John Heywood, Professor of Mechanical Engineering at MIT; Sun Jae Professor, Emeritus
  2. http://green.autoblog.com/2013/06/26/new-vw-golf-tdi-bluemotion-is-most-fuel-efficient-ever-with-73/
  3. http://www.eia.gov/tools/faqs/faq.cfm?id=307&t=11

Authors and Editors

Bethel Afework, Jordan Hanania, James Jenden, Kailyn Stenhouse, Jason Donev
Last updated: September 3, 2018
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