Fuel Economy Converter

Convert seamlessly between MPG (US & UK), km/L, and Liters per 100km ($L/100km$). Analyze trip fuel expenses and carbon footprints instantly.

5 mpg (Hummer H1) Slide to Scale 100 mpg (Plug-in Hybrid)
Trip Expense & Carbon Footprint Estimator
Active Eco-Efficiency Dashboard
Left dial monitors relative Eco-rating. Right cylinder displays real-time fuel burn footprint levels.
Converted Equivalent Sizing
9.408
Liters per 100 km (L/100km)
Estimated Trip Fuel Cost
$14.00
Requires 4.0 gallons of fuel
Carbon Dioxide Footprint
35.55 kg
Equal to charging 4,320 smartphones
Total Vehicle Range
Based on your configured tank size
375.0 miles
Multiplication Factor / Formula
Standard translation method
235.21 / mpg

Standard Fuel Economy Equivalences

Vehicle / Benchmark Economy
MPG (US) Equivalent
Metric equivalent & Environmental Classification

Equivalent Structural Conversions

Unit Type
Relative Equivalent
Standard Notation

Calculation History Log

Time Stamp Original Input From Unit Result Value Converted Unit
No computations recorded yet.

1. Physics of Fuel Economy Sizing

In thermodynamics, automotive mechanics, and transport logistics, Fuel Economy represents the volumetric efficiency or specific consumption of energy required to propel a vehicle across a set distance. Unlike simple linear dimension variables, fuel economics are represented in two distinct physical models:

This inverse relationship dictates that converting between MPG and $L/100km$ requires reciprocal division formulas:

$$L/100km = \frac{235.214583}{MPG_{US}}$$ $$L/100km = \frac{282.480936}{MPG_{UK}}$$ EXPLORE OUR PRECISION VOLUME CONVERTER

2. Key Fuel Economy Standards

This workspace tracks precise fuel metrics used globally:

Frequently Asked Questions

Why do US and UK MPG ratings differ?

An Imperial Gallon is approximately 20% larger than a US Gallon ($4.546 \text{ Liters}$ vs. $3.785 \text{ Liters}$). Consequently, a car that achieves $30 \text{ MPG US}$ will mathematically report $36 \text{ MPG UK}$ without any actual physical change to its thermal efficiency.

How is the carbon footprint calculated?

The Environmental Protection Agency (EPA) standards dictate that burning 1 gallon of standard unleaded gasoline releases approximately $8.887 \text{ kg}$ ($19.6 \text{ lbs}$) of $CO_2$ gas. Diesel releases more carbon per gallon ($10.180 \text{ kg}$) due to its heavier molecular structure, though diesel engines often burn fewer total gallons over a set distance.

What is a good fuel economy rating?

A rating below $6.0 \text{ L/100km}$ (or above $40 \text{ MPG US}$) is generally considered highly efficient. Modern hybrid and electric vehicles (using MPG equivalent or MPGe metrics) routinely surpass $100 \text{ MPG}$ equivalents.