When to use this calculator
Calculate fuel economy using US liquid gallons and miles. Uses the US liquid gallon, not the UK imperial gallon.
Explore the fuel use & cost calculators for other questions in this topic. For a related calculation, use the Average Speed for Equal Distances Calculator: Find average speed for two equal-distance legs at different speeds.
PUTTING IT INTO PRACTICE
Miles Per Gallon US: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Miles travelled | 300 |
| Fuel used (litres) | 30 |
| Result | 37.854118 US mpg |
- Check the input labels and enter the example values above.
- Apply the relationship: US MPG = miles × 3.785411784 ÷ litres.
- The result is 37.854118 US mpg, rounded for display.
How to interpret your result
Uses the US liquid gallon, not the UK imperial gallon.
State the fuel-economy convention: UK imperial and US liquid gallons have different volumes. L/100 km is consumption, so lower values indicate less fuel used per distance. Input prices are scenario values.
Frequently asked questions
Are UK MPG and US MPG comparable without conversion?
No. Both use miles but different gallon volumes, so their numerical values differ for the same vehicle consumption.
How do I use the miles per gallon us calculator?
Enter miles travelled, fuel used (litres). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
US MPG = miles × 3.785411784 ÷ litres.
What should I check before using the result?
Uses the US liquid gallon, not the UK imperial gallon.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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