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Learn how to convert between miles per gallon (MPG) and liters per 100 kilometers (L/100km) to accurately budget road trip fuel expenses.
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Planning a cross-country road trip or comparing new cars requires understanding fuel economy metrics. In North America, drivers evaluate efficiency using Miles Per Gallon (MPG), while Europe, Australia, and most metric nations use Liters per 100 Kilometers (L/100km).
Consider this question: Which upgrade saves more fuel over 10,000 miles?
Most people intuitively guess Option B. But mathematically, Option A saves vastly more fuel:
Because MPG measures distance per unit of fuel rather than fuel per unit of distance, consumer intuition is often misled. L/100km avoids this confusion completely.
Calculate trip fuel requirements, round-trip expenses, and unit conversions with our free Fuel Efficiency Calculator.
L/100km = 235.215 / MPG (using US gallons). For UK imperial gallons, L/100km = 282.481 / MPG.
L/100km has a linear relationship with fuel consumed and cost, whereas MPG is non-linear (the MPG illusion, where upgrading from 10 to 20 MPG saves far more gas than 30 to 40 MPG).
Technical Architect & Lead Developer • ToolsHub Pro
Abdul Nabi is a senior software engineer and technical architect specializing in client-side Web APIs, high-performance browser computing, cryptographic validation, and privacy-first digital utility platforms. All guides on ToolsHub Pro are peer-reviewed for mathematical rigor and developer accuracy.