How do I convert MPG to L/100km?

To convert MPG (US) to L/100km, divide 235.215 by the MPG value. For example, 30 MPG = 235.215 ÷ 30 = 7.84 L/100km. Our calculator does this automatically for you, including adjustments for US vs UK gallons.

What is the difference between US MPG and UK MPG?

US MPG and UK MPG use different gallon sizes. A US gallon is 3.785 liters while a UK (Imperial) gallon is 4.546 liters. This means UK MPG figures are about 20% higher than US MPG for the same vehicle. 30 US MPG equals approximately 36 UK MPG.

What is good fuel economy for a car?

Good fuel economy varies by vehicle type. For cars: 30-40 MPG (7.8-5.9 L/100km) is good, 40+ MPG is excellent. For SUVs: 25-30 MPG is good. For trucks: 20-25 MPG is good. Hybrids typically achieve 40-60 MPG, while EVs can reach 100+ MPGe.

How is L/100km different from km/L?

L/100km measures how many liters of fuel are needed to travel 100 kilometers (lower is better). km/L measures how many kilometers you can travel per liter of fuel (higher is better). To convert: km/L = 100 ÷ L/100km. For example, 8 L/100km = 12.5 km/L.

What is MPGe for electric vehicles?

MPGe (Miles Per Gallon equivalent) is a measure of how far an electric vehicle can travel on the energy equivalent of one gallon of gasoline (33.7 kWh). A typical EV achieves 100-130 MPGe, meaning they're 3-4 times more efficient than gas cars.

Why is my real-world fuel economy different from EPA ratings?

EPA ratings are based on standardized tests that don't fully represent real driving conditions. Real-world fuel economy can be 10-20% lower due to: aggressive driving, high speeds, extreme temperatures, short trips, cargo weight, roof racks, tire pressure, and A/C usage.

How do I calculate my annual fuel cost?

Annual fuel cost = (Annual miles ÷ MPG) × Fuel price per gallon. For example: 12,000 miles ÷ 30 MPG × $3.50/gallon = $1,400/year. Our calculator automates this and includes options for different fuel types and regional prices.

How much CO2 does my car produce?

Gasoline produces about 8.89 kg of CO2 per gallon (2.35 kg per liter). Diesel produces about 10.18 kg per gallon (2.69 kg per liter). A 30 MPG car driving 12,000 miles/year produces about 3.5 metric tons of CO2 annually.

What affects fuel economy the most?

The biggest factors affecting fuel economy are: 1) Driving speed (fuel economy drops significantly above 50 mph), 2) Aggressive acceleration/braking, 3) Vehicle weight and cargo, 4) Tire pressure (each 1 PSI drop costs ~0.2% efficiency), 5) Air conditioning use, 6) Cold weather operation.

Is diesel or gasoline more fuel efficient?

Diesel engines are typically 25-35% more fuel efficient than gasoline engines due to higher compression ratios and energy density. However, diesel fuel is often more expensive and produces more NOx and particulate emissions. For long-distance highway driving, diesel is usually more economical.

How do I convert between WLTP and EPA fuel economy?

WLTP (European) ratings are typically 5-15% more optimistic than EPA (US) ratings. As a rough conversion: EPA MPG ≈ WLTP MPG × 0.85-0.95. Our calculator includes both standards and allows easy comparison.

What is the most fuel efficient speed to drive?

The most fuel-efficient speed for most vehicles is between 45-65 mph (72-105 km/h). Above 65 mph, aerodynamic drag increases significantly, reducing fuel economy by about 1% for every 1 mph increase. Highway cruising at 55-60 mph is optimal for most vehicles.

How do I convert MPG to L/100km?

To convert MPG (US) to L/100km, divide 235.215 by the MPG value. For example, 30 MPG = 235.215 ÷ 30 = 7.84 L/100km. For UK MPG, divide 282.481 by the MPG value. Our calculator handles all conversions automatically.

What is the difference between US MPG and UK MPG?

US MPG uses US gallons (3.785 liters) while UK MPG uses Imperial gallons (4.546 liters). This means UK MPG figures are approximately 20% higher than US MPG for the same fuel consumption. A car rated at 30 US MPG would be rated at about 36 UK MPG.

What is considered good fuel economy?

Good fuel economy varies by vehicle type. For sedans: 30-40 MPG is good, 40+ is excellent. For SUVs: 25-30 MPG is good. For trucks: 20-25 MPG is good. Hybrids typically achieve 40-60 MPG, while electric vehicles can reach 100+ MPGe equivalent.

What is MPGe for electric vehicles?

MPGe (Miles Per Gallon equivalent) measures EV efficiency using the energy equivalent of one gallon of gasoline (33.7 kWh). A 100 MPGe EV is about 3 times more efficient than a 30 MPG gas car. Most EVs achieve 80-140 MPGe.

Why is my real-world MPG lower than the EPA rating?

Real-world MPG is often 10-20% lower than EPA ratings due to: aggressive driving, highway speeds over 65 mph, cold weather, short trips, heavy cargo, improper tire pressure, and A/C use. Our calculator includes driving style adjustments to estimate real-world consumption.

How do I calculate annual fuel cost?

Annual fuel cost = (Annual miles ÷ MPG) × Fuel price per gallon. For example: 12,000 miles ÷ 30 MPG × $3.50/gallon = $1,400/year. Our calculator provides automatic cost estimates based on your inputs and local fuel prices.

How much CO2 does my car produce?

Gasoline produces 8.89 kg of CO2 per gallon, diesel produces 10.18 kg per gallon. A car averaging 30 MPG driving 12,000 miles produces about 3.6 metric tons of CO2 annually. You would need approximately 165 trees to offset this carbon.

Is diesel more fuel efficient than gasoline?

Diesel engines are typically 25-35% more fuel efficient than gasoline engines due to higher compression ratios and greater energy density of diesel fuel. However, diesel fuel often costs more and has higher CO2 emissions per gallon.

What speed is most fuel efficient?

The most fuel-efficient speed is typically 45-65 mph (72-105 km/h). Above 65 mph, aerodynamic drag increases significantly - each 5 mph over 50 mph is like paying an extra $0.20 per gallon. Cruise control at moderate highway speeds optimizes efficiency.

How does temperature affect fuel economy?

Cold weather can reduce fuel economy by 15-35%. At 20°F (-7°C), short trips can see up to 35% reduction. This is due to increased engine warm-up time, higher fuel viscosity, winter fuel blends, and heating system use. EVs can see even greater cold-weather impacts.

What is the WLTP vs EPA difference?

WLTP (European) ratings are typically 5-15% more optimistic than EPA (US) ratings due to different test procedures. EPA tests include more aggressive driving and A/C use. As a rough conversion: EPA MPG ≈ WLTP MPG × 0.85-0.95.

How do I improve my fuel economy?

Key tips: 1) Drive smoothly (avoid rapid acceleration/braking), 2) Maintain proper tire pressure, 3) Remove excess weight and roof racks, 4) Use cruise control on highways, 5) Avoid excessive idling, 6) Keep up with maintenance, 7) Plan efficient routes, 8) Drive at moderate speeds.

Fuel Economy Converter

Convert between MPG, L/100km, km/L and all fuel economy units. Compare 100+ vehicles, calculate costs with live fuel prices, and track CO2 emissions.

12 Unit Conversions100+ Vehicles20 CountriesCO2 Calculator

Enter Fuel Economy

Value

Unit

US standard fuel economy measure

Driving Style

Typical driving patterns

Cost Calculator

Annual Miles

Fuel Price ($/gal)

Trip Distance (miles)

Enter a fuel economy value to see conversions

Understanding Units

MPG (US): Miles per US gallon. Higher is better. Standard in USA.

L/100km: Liters per 100km. Lower is better. Standard in Europe, Canada, Australia.

km/L: Kilometers per liter. Higher is better. Common in Japan, India, Brazil.

Improve Your MPG

Drive smoothly: Avoid rapid acceleration and hard braking.

Maintain speed: Use cruise control on highways.

Check tires: Low pressure costs ~0.2% efficiency per PSI.

EV Efficiency (MPGe)

What is MPGe? Energy equivalent of one gallon (33.7 kWh).

Typical EVs: 80-140 MPGe, 3-4x more efficient than gas cars.

Best performers: Lucid Air (140 MPGe), Hyundai IONIQ 6 (130 MPGe).

Frequently Asked Questions

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What Users Say

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“I use this for my European car with L/100km specs. Perfect for understanding real-world costs in the US.”

Maria S.

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“The vehicle comparison feature helped me choose between a hybrid and gas model. Saved $500/year in fuel!”

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Daily Commuter

“As a fleet manager, the CO2 calculations help with our sustainability reporting. Excellent tool!”

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