Mileage Calculator | Fuel Economy (MPG, L/100km) & Trip Cost

📖 How to Use This Mileage Calculator

Choose calculation mode - Select "Fuel Economy" or "Trip Cost".

For Fuel Economy: Enter distance traveled and fuel used to calculate MPG, L/100km, and km/L.

For Trip Cost: Enter trip distance, fuel economy, and fuel price to estimate total cost.

⛽ Understanding Fuel Economy Measurements

MPG (Miles Per Gallon): Common in USA and UK. Higher MPG = better fuel efficiency. Example: 30 MPG means 30 miles per 1 gallon of fuel.
L/100km (Liters per 100 kilometers): Common in Europe, Asia, and Australia. Lower L/100km = better fuel efficiency. Example: 8 L/100km means 8 liters per 100 km traveled.
km/L (Kilometers per Liter): Used in many countries. Higher km/L = better efficiency. Example: 12.5 km/L.
MPG (UK): UK gallon is larger (4.546 liters) vs US gallon (3.785 liters). UK MPG numbers appear higher than US MPG for the same vehicle.

📊 Fuel Economy Formulas

MPG (US) = Distance (miles) ÷ Fuel (gallons)
L/100km = (Fuel in liters × 100) ÷ Distance (km)
km/L = Distance (km) ÷ Fuel (liters)
Conversion: 235.215 ÷ MPG = L/100km

💡 Tips to Improve Fuel Economy

Check tire pressure: Under-inflated tires can reduce MPG by 0.3% per 1 PSI drop
Remove excess weight: Every 100 lbs reduces MPG by about 1%
Drive smoothly: Aggressive acceleration and braking can lower MPG by 15-30% on highways
Reduce speed: MPG decreases rapidly above 50 mph (80 km/h)
Use cruise control: Maintains steady speed on highways
Keep up with maintenance: Clean air filters, proper oil, and tuned engine

❓ Frequently Asked Questions (FAQ)

What is a good MPG for a car?

Good MPG varies by vehicle type: Small cars: 30-40 MPG; SUVs: 20-28 MPG; Trucks: 15-22 MPG; Hybrids: 40-60 MPG; Electric vehicles: equivalent 100-120 MPGe.

How do I convert between MPG and L/100km?

Use these formulas: L/100km = 235.215 ÷ MPG | MPG = 235.215 ÷ L/100km. Our calculator shows both values automatically.

Why does my actual MPG differ from EPA estimates?

EPA estimates are lab-tested under ideal conditions. Real-world MPG varies based on driving habits, traffic, terrain, weather, and vehicle maintenance. Typical real-world MPG is 10-20% lower.

What's the difference between US and UK gallons?

US gallon = 3.785 liters; UK (Imperial) gallon = 4.546 liters. UK MPG numbers are about 20% higher than US MPG for the same vehicle. Our calculator shows both MPG (US) and MPG (UK).

How often should I calculate my fuel economy?

Track your fuel economy every fill-up to monitor vehicle health. A sudden drop in MPG may indicate maintenance issues like low tire pressure, dirty air filter, or engine problems.

Does air conditioning affect fuel economy?

Yes, AC can reduce fuel economy by 5-25% depending on conditions. At highway speeds, using AC is more efficient than opening windows due to aerodynamic drag. At low speeds, windows may be more efficient.