How to convert miles per gallon to US gallons per 100 miles
gal/100 mi = 100 ÷ mpgMiles per gallon and US gallons per 100 miles are inversely related: when one goes up the other goes down. Divide 100 by the value — do not multiply.
Worked examples
- 1 mile per US gallon100 ÷ 1 = 100 gal/100 mi
- 5 miles per gallon (US)100 ÷ 5 = 20 gal/100 mi
- 10 miles per gallon (US)100 ÷ 10 = 10 gal/100 mi
- 20 miles per gallon (US)100 ÷ 20 = 5 gal/100 mi
- 100 miles per gallon (US)100 ÷ 100 = 1 gal/100 mi
Miles per gallon (US) to US gallons per 100 miles conversion table
Values are calculated by the conversion engine using the full formula and rounded to 8 significant figures.
| Miles per gallon (mpg) | US gallons per 100 miles (gal/100 mi) |
|---|---|
| 10 mpg | 10 gal/100 mi |
| 12 mpg | 8.3333333 gal/100 mi |
| 15 mpg | 6.6666667 gal/100 mi |
| 18 mpg | 5.5555556 gal/100 mi |
| 20 mpg | 5 gal/100 mi |
| 22 mpg | 4.5454545 gal/100 mi |
| 25 mpg | 4 gal/100 mi |
| 28 mpg | 3.5714286 gal/100 mi |
| 30 mpg | 3.3333333 gal/100 mi |
| Miles per gallon (mpg) | US gallons per 100 miles (gal/100 mi) |
|---|---|
| 32 mpg | 3.125 gal/100 mi |
| 35 mpg | 2.8571429 gal/100 mi |
| 40 mpg | 2.5 gal/100 mi |
| 45 mpg | 2.2222222 gal/100 mi |
| 50 mpg | 2 gal/100 mi |
| 55 mpg | 1.8181818 gal/100 mi |
| 60 mpg | 1.6666667 gal/100 mi |
| 70 mpg | 1.4285714 gal/100 mi |
| 100 mpg | 1 gal/100 mi |
About the units
Mile per US gallon (mpg)
Miles travelled per US gallon — higher is better. The standard in the United States. One mile per US gallon equals 0.4251437074 kilometers per liter (km/L).
US gallon per 100 miles (gal/100 mi)
Shown on US EPA fuel-economy labels alongside mpg. It is inversely related to kilometers per liter: km/L = 42.51437074 ÷ value.
Frequently asked questions
What is the formula to convert miles per gallon to US gallons per 100 miles?
gal/100 mi = 100 ÷ mpg. Miles per gallon and US gallons per 100 miles are inversely related: when one goes up the other goes down. Divide 100 by the value — do not multiply.
What is 5 miles per gallon (US) in US gallons per 100 miles?
5 mpg = 20 gal/100 mi.
Why is this not a simple multiplication?
One unit measures the quantity directly and the other measures its inverse, so a larger value in one means a smaller value in the other. That is why the formula divides a constant by your value.
Is this mpg to gal/100 mi converter accurate?
Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.
Convert miles per gallon (US) to other units
- Miles per gallon (US) to liters per 100 kilometers
- Miles per gallon (US) to miles per gallon (UK)
- Miles per gallon (US) to kilometers per liter