b2KIT

Fuel Economy MPG Converter

Convert MPG, L/100km, km/L, and miles per imperial gallon for any vehicle.

Tested tool guide Tested browser tools Checked August 16, 2026

What Fuel Economy MPG Converter does, with a checked example

Enter one observed or published fuel-economy figure and identify whether it is US MPG, imperial MPG, liters per 100 kilometers, or kilometers per liter. The converter reports the equivalent values in the other three scales while preserving the same distance and fuel quantity. It changes units only; it does not estimate consumption from vehicle type, speed, or trip length. The common trap is treating MPG as unqualified: US and imperial gallons have different volumes, so their MPG figures are not interchangeable.

Worked example

A concrete input and expected output from the current implementation.

Input

10 km/L

Expected output

10 L/100 km, approximately 23.52 MPG (US), and approximately 28.25 MPG (Imperial)

At 10 kilometers per liter, traveling 100 kilometers consumes exactly 10 liters. Converting the same rate with 1 mile equal to 1.609344 kilometers, a US gallon equal to 3.785411784 liters, and an imperial gallon equal to 4.54609 liters produces the two MPG values.

How the result is produced

1

Converting the ratios

Fuel economy can be a distance-per-volume ratio, such as MPG or km/L, or a volume-per-distance ratio, such as L/100 km. The conversion preserves the underlying distance and fuel volume. It uses 1.609344 kilometers per mile, 3.785411784 liters per US gallon, and 4.54609 liters per imperial gallon.

2

Reading opposite scales

Converting km/L to L/100 km takes the reciprocal and scales it by 100: L/100 km equals 100 divided by km/L. MPG behaves like km/L, so higher values mean less fuel used per distance. L/100 km runs in the opposite direction. For identical efficiency, imperial MPG is about 20.1 percent higher than US MPG because the imperial gallon is larger.

Good uses

  • Translate a US MPG rating into L/100 km before comparing it with specifications published for vehicles in countries that use metric fuel consumption.
  • Convert a dashboard or mileage-log value recorded in km/L into both US and imperial MPG for a report shared across regions.
  • Express an imperial MPG figure from a British vehicle listing in US MPG without mistakenly treating the two gallon definitions as equal.

Limits and checks

  • Confirm whether an MPG source means US or imperial gallons. If the source omits the gallon type, the conversion is ambiguous and the two possible results differ by about 20.1 percent.
  • Treat the result as a unit conversion, not a prediction. Traffic, temperature, driving style, load, terrain, fuel blend, and test procedure can make real consumption differ from the entered rating.
  • Do not compare converted ratings from different official test cycles as though conversion made the tests equivalent. Unit conversion preserves each reported number but does not reconcile different routes, speeds, temperatures, or measurement rules.

Common questions

Why does a better MPG rating produce a smaller L/100 km value?

MPG measures distance obtained from a fixed fuel volume, while L/100 km measures fuel consumed over a fixed distance. One therefore increases as the other decreases. For US MPG, L/100 km is approximately 235.214583 divided by MPG. Because this is a reciprocal relationship, equal MPG increases do not represent equal reductions in fuel consumption.

Can this converter calculate how much fuel my trip will use?

No. It converts an existing fuel-economy or fuel-consumption rate into equivalent units. Calculating trip fuel requires both the trip distance and a suitable consumption rate. For example, with a rating in L/100 km, multiply that rating by the trip distance in kilometers and divide by 100. Actual use may still differ from the rating.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.

Related Tools

Checklist Maker

Create customizable checklists with groups, due dates, and priorities for any project.

Daily Planner Creator

Design a printable daily planner with time blocks, goals, and priority sections.

Typing Speed Test

Measure your typing speed in WPM and accuracy with real-time feedback and stats.

Focus Timer with Ambient Sounds

Pomodoro timer with built-in ambient noise (rain, cafe, forest) generated via Web Audio API oscillators.

Pomodoro Timer

Stay focused with a customizable Pomodoro timer featuring work and break intervals.

Stopwatch

A precise stopwatch with lap tracking, split times, and exportable results.