Fuel Economy Converter
Convert vehicle fuel economy labels across US mpg, imperial mpg, kilometers per liter, and liters per 100 kilometers. The tool makes reciprocal fuel-consumption units visible so lower L/100 km values are not confused with higher mpg values.
Base route
km/L
Supported units
4
Includes
mpg + L/100 km
Live converter
Fuel economy inputs
Convert distance-per-fuel and fuel-per-distance labels across US mpg, imperial mpg, kilometers per liter, and liters per 100 kilometers.
Converted result
7.8404861111 L/100 km
Input
30 mpg (US)
Output unit
L/100 km
Base method
km per liter
Liters per 100 kilometers is an inverse fuel-consumption unit, so lower numbers indicate better economy.
Fuel economy in every supported unit
| Unit | Converted value | Unit name | Note |
|---|---|---|---|
| mpg (US) | 30 | Miles per US gallon | Distance per US liquid gallon. |
| mpg (Imp) | 36.0284977651 | Miles per imperial gallon | Distance per imperial gallon. |
| km/L | 12.7543112229 | Kilometers per liter | Distance per liter. |
| L/100 km | 7.8404861111 | Liters per 100 kilometers | Fuel consumed per 100 kilometers; lower is better. |
Compare vehicle efficiency labels without mixing systems
Car research
Compare listings or reviews that quote US mpg, imperial mpg, km/L, or L/100 km.
Trip notes
Convert dashboard or manual readings into the label used by your budget, region, or spreadsheet.
Fleet checks
Keep reciprocal fuel-consumption values visible when comparing mixed vehicle data sources.
Fuel economy conversion formula
The converter uses kilometers per liter as the base route. Liters per 100 kilometers is the reciprocal form, so it must be inverted rather than multiplied by a simple factor.
Working formulas
US mpg to km/L
km/L = mpg x 1.609344 / 3.785411784
One mile is 1.609344 km and one US gallon is 3.785411784 L.
km/L to L/100 km
L/100 km = 100 / km/L
This reciprocal step is why lower L/100 km values indicate better economy.
Imperial mpg to km/L
km/L = mpg(Imp) x 1.609344 / 4.54609
Imperial gallons are larger than US liquid gallons.
Symbols
- mpg - miles per gallon
- Distance traveled per gallon of fuel.
- L/100 km - fuel consumed per distance
- Liters needed to travel 100 kilometers.
Why fuel economy conversions need the inverse check
Prevents direction mistakes
- Higher mpg and km/L values are better, while lower L/100 km values are better.
- The table keeps all four labels visible so the reciprocal relationship is easier to audit.
- US and imperial gallons are separate, preventing a common vehicle-listing mismatch.
Better vehicle comparisons
- Regional ratings can be translated into the unit used by your spreadsheet or buying checklist.
- The method uses exact mile, US gallon, and imperial gallon relationships.
- Trip-computer readings can be compared with published ratings without manual formula work.
Useful for vehicle and travel decisions
Car shoppers
Translate fuel economy labels when comparing vehicles from different countries or review sources.
Fleet managers
Normalize mixed mpg and L/100 km records before cost or emissions analysis.
Travel planners
Convert efficiency assumptions before estimating fuel use for road trips.
How it works in three quick steps.
Enter the vehicle rating
Type the fuel economy value from a window sticker, manual, trip computer, or comparison table.
Choose fuel economy labels
Select US mpg, imperial mpg, kilometers per liter, or liters per 100 kilometers.
Check the inverse unit
Remember that L/100 km measures fuel consumed per distance, so a lower value is better.
Save fuel economy comparisons
Copy labeled results
Copy the selected conversion with source and target unit labels for recipes, vehicle notes, utility comparisons, or homework.
Print the comparison table
Print the full table when repeated conversions need to stay visible at a counter, desk, shop, lab, or classroom.
Keep the method nearby
Use the formula notes to confirm whether the converter used milliliters, km/L, joules, or watts as the base route.
About this fuel economy converter
Fuel economy labels are not all the same kind of measurement. Miles per gallon and kilometers per liter describe distance per fuel volume, so bigger numbers are better. Liters per 100 kilometers describes fuel volume per distance, so smaller numbers are better. Treating all labels as direct multipliers can reverse the meaning of a result.
This converter uses kilometers per liter as the internal route because it provides a clear bridge between distance-per-fuel units and L/100 km. US mpg uses the US liquid gallon, imperial mpg uses the imperial gallon, and L/100 km is converted with a reciprocal formula. That makes the table useful for car research, fleet notes, road-trip estimates, and spreadsheet cleanup.
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