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Professional scenario conversions

Fuel economy: mpg vs L/100km

mpg and L/100km describe fuel efficiency from opposite directions, so interpretation can easily flip.

Fleet and consumer decisions still need cost per distance, not only the efficiency number—fuel price, duty cycle, and cold-start share matter.

Key takeaways

  • Higher mpg is better; lower L/100km is better—say it out loud when onboarding.
  • Confirm US vs imperial gallon before any mpg math with UK sources.
  • Normalize mixed fleets to one column (L/100km or kWh/100km) before KPI rollups.
  • Compare EV kWh/100km to ICE using energy price, not headline mpg alone.

How to convert

30 US = 7.8405 L/100km

Interpretation rule

Higher mpg means better efficiency; lower L/100km means better efficiency.

Regional context

North American specs often use mpg, while many other regions use L/100km. Normalize before comparing models.

Cost perspective

Final decision should include local fuel price and yearly mileage, not unit conversion alone.

Imperial vs US gallon trap

If fuel volume is quoted in gallons, confirm which gallon definition applies before mpg math.

Electricity equivalent

For EVs, kWh/100 km replaces L/100km; do not compare mpg of ICE directly to EV efficiency without energy cost context.

Fleet reporting

Normalize mixed fleets to a single efficiency column (e.g., L/100km or kWh/100km) before aggregating KPIs.

FAQ

Is a higher mpg always cheaper to run?
Not if fuel type, price, or driving pattern differs. Use cost per distance with local prices.

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