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Free Fuel Economy Converter – MPG, km/L & L/100km

Fuel Economy Converter changes MPG, km/l, and L/100km instantly online for free. Compare fuel efficiency across units in your browser.

MPG · km/L · L/100kmUS & UK GallonsReal-timeCopy ResultsFree

Converted Values

MPG (US)
30
MPG (UK)
36.0285
km/L
12.7543
L/100km
7.8405

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All conversions run locally in your browser. Nothing is uploaded.

How to Use Fuel Economy Converter

1

Enter a Value

Type your fuel economy into the unit you know, such as MPG or L/100km.

2

Read Every Unit

All other units update instantly so you can compare efficiency.

3

Copy the Result

Copy the converted figure you need for your comparison.

Convert Between MPG, km/L, and L/100km Instantly

The Helperzy Fuel Economy Converter translates a vehicle's fuel efficiency between the main systems used worldwide: miles per gallon (US and UK), kilometers per liter, and liters per 100 kilometers. Enter a figure in one unit and the others update at once, so you can compare cars no matter which standard a spec sheet uses. Fuel economy is uniquely tricky because some units measure distance per fuel (higher is better, like MPG and km/L) while others measure fuel per distance (lower is better, like L/100km). These are inversely related, not linear, so you cannot simply multiply by a fixed factor — the converter handles the reciprocal math correctly so the comparison is accurate. Drivers use it to compare a car advertised in MPG against one rated in L/100km, to understand efficiency when buying or importing a vehicle, and to convert their own observed mileage into a familiar unit. The US and UK gallons differ, so the tool distinguishes them to avoid a common error. All calculations run locally in your browser, so the tool is fast, works without an internet connection once loaded, and never uploads anything. Your figures stay private on your own device.

Frequently Asked Questions – Fuel Economy Converter

Enter your value in the MPG field and the L/100km result appears instantly. Because these units are inversely related, the Helperzy converter uses the correct reciprocal formula rather than a simple multiplication, so the result is accurate.