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Translate between MPG (US/UK), L/100km and km/L consumption figures.
Translate between MPG (US/UK), L/100km and km/L consumption figures.
Enter values above and click Calculate — results will appear here with the formula explained.
Fuel economy speaks two dialects. Distance-per-fuel (MPG, km/L) rises when efficiency improves; consumption-per-distance (L/100km) falls instead. Both describe the same tank behavior, and converting requires division rather than simple scaling.
The UK gallon compounds confusion: at 4.546 liters it dwarfs the US gallon's 3.785, so UK MPG figures run about 20% higher for identical vehicles. Always confirm which gallon before comparing spec sheets across the Atlantic.
MPG misleads on savings because it's reciprocal: improving 10→20 mpg saves five times more fuel than 30→40 mpg over the same miles. L/100km is linear — each point cut saves the same fuel — which is why engineers prefer it and why 'a few MPG' means wildly different things at different baselines.
Real-world gaps vs ratings: EPA/WLTP lab figures run 15–30% optimistic versus aggressive driving, winter cold, short trips, roof boxes and underinflated tires. Hybrids suffer most in winter (engine runs for heat); EVs lose 20–40% range in freezing weather. Use ratings for comparison, trip computers for truth.
Cost math closes the loop: annual fuel = miles ÷ mpg × price (or km ÷ 100 × L/100km × price). At 12,000 miles/year, $3.50/gal, moving 25→35 mpg saves ~$480 yearly — the number that prices hybrid premiums and EV comparisons honestly.
EV translation: MPGe (miles per 33.7 kWh gallon-equivalent) and kWh/100km or miles/kWh let electrics join the comparison — 3.5 mi/kWh ≈ 118 MPGe. Charging costs vary more than gasoline (home $0.15 vs DC fast $0.50+/kWh), so per-mile EV cost spans wider than any gas comparison.
Translate between MPG (US/UK), L/100km and km/L consumption figures. Formula: L/100km = 100 ÷ (km per liter). Example: A European car rated 6.5 L/100km delivers 36.2 MPG-US and 43.5 MPG-UK — same car, three very different-looking numbers.
Fuel economy speaks two dialects. Distance-per-fuel (MPG, km/L) rises when efficiency improves; consumption-per-distance (L/100km) falls instead. Both describe the same tank behavior, and converting requires division rather than simple scaling.
The UK gallon compounds confusion: at 4.546 liters it dwarfs the US gallon's 3.785, so UK MPG figures run about 20% higher for identical vehicles. Always confirm which gallon before comparing spec sheets across the Atlantic.
MPG misleads on savings because it's reciprocal: improving 10→20 mpg saves five times more fuel than 30→40 mpg over the same miles. L/100km is linear — each point cut saves the same fuel — which is why engineers prefer it and why 'a few MPG' means wildly different things at different baselines.
Real-world gaps vs ratings: EPA/WLTP lab figures run 15–30% optimistic versus aggressive driving, winter cold, short trips, roof boxes and underinflated tires. Hybrids suffer most in winter (engine runs for heat); EVs lose 20–40% range in freezing weather. Use ratings for comparison, trip computers for truth.
Cost math closes the loop: annual fuel = miles ÷ mpg × price (or km ÷ 100 × L/100km × price). At 12,000 miles/year, $3.50/gal, moving 25→35 mpg saves ~$480 yearly — the number that prices hybrid premiums and EV comparisons honestly.
EV translation: MPGe (miles per 33.7 kWh gallon-equivalent) and kWh/100km or miles/kWh let electrics join the comparison — 3.5 mi/kWh ≈ 118 MPGe. Charging costs vary more than gasoline (home $0.15 vs DC fast $0.50+/kWh), so per-mile EV cost spans wider than any gas comparison.
A European car rated 6.5 L/100km delivers 36.2 MPG-US and 43.5 MPG-UK — same car, three very different-looking numbers. Improving 10→20 mpg (US) saves ~600 gal yearly at 12k miles; 30→40 mpg saves only ~100 — reciprocals punish low baselines most.
Formulas are standard public references (see our methodology). External standards are cited in the text where they apply.
Last reviewed: September 2026 · Report an error