MPG Calculator: Miles Per Gallon & Trip Fuel Cost
Calculate miles per gallon (MPG), L/100km, and fuel trip costs.
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How to Use the MPG Calculator: Miles Per Gallon & Trip Fuel Cost
- 1Enter distance driven (miles or kilometers).
- 2Enter fuel consumed (gallons or liters).
- 3Optionally enter fuel price per gallon/liter.
- 4View MPG, L/100km, cost per mile, and total trip cost.
Formula & How It Works
Miles Per Gallon Formula
MPG = Distance in Miles / Fuel in Gallons. L/100km = 235.215 / US MPG.
Worked Examples
Full Tank Highway
Input: 350 miles on 10 gallons at $3.50/gal
Explanation: 350 / 10 = 35 MPG.
Commuter Sedan
Input: 240 miles on 8.5 gallons
Explanation: 240 / 8.5 = 28.235 MPG.
Pickup Truck
Input: 280 miles on 17.5 gallons
Explanation: 280 / 17.5 = 16.0 MPG.
Frequently Asked Questions
How do you calculate MPG manually?▼
Fill your tank, reset trip odometer, drive, refill your tank to full, and divide trip miles by gallons pumped.
How do you convert MPG to L/100km?▼
Divide 235.215 by the US MPG value (e.g. 235.215 / 30 MPG = 7.84 L/100km).
Why is UK MPG higher than US MPG?▼
A UK imperial gallon is ~20% larger than a US liquid gallon (4.546 L vs 3.785 L), resulting in higher MPG numbers.
What is good gas mileage?▼
Over 30 MPG for highway driving is generally considered good for gasoline cars, while hybrids often achieve 45 to 55+ MPG.
What is the formula for trip fuel cost?▼
Trip Cost = (Miles Driven / MPG) * Price Per Gallon.
Is this tool free?▼
Yes, Toolzy automotive tools are 100% free and client-side.
Quick Reference & Conversion Table
| Vehicle Class | Typical US MPG | Metric L/100km | Cost / 1,000 Miles (@ $3.50/gal) |
|---|---|---|---|
| Hybrid Sedan | 50.0 MPG | 4.7 L/100km | $70.00 |
| Compact Car | 35.0 MPG | 6.7 L/100km | $100.00 |
| Midsize Crossover | 28.0 MPG | 8.4 L/100km | $125.00 |
| Full-Size SUV | 18.0 MPG | 13.1 L/100km | $194.44 |
| Heavy Duty Truck | 14.0 MPG | 16.8 L/100km | $250.00 |
⚠️ Common Pitfalls to Avoid
- •Confusing US gallons (3.785 L) with UK Imperial gallons (4.546 L).
- •Relying solely on vehicle dashboard displays without manual tank-to-tank pump checks.
💡 Practical Real-World Uses
- •Auditing real-world vehicle gas mileage against EPA window sticker estimates.
- •Calculating road trip gas cost splitting among travel companions.
- •Tracking fuel consumption changes indicating mechanical engine issues.
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