Gas Mileage Calculator

How to Use This Calculator

Track your actual fuel efficiency by recording fill-ups. Here's how to calculate your real-world MPG:

1. Fill your tank completely and note your odometer reading (or reset your trip odometer).
2. Drive normally until you need to refuel.
3. Fill up again and record the gallons pumped and new odometer reading.
4. Enter the miles driven and gallons used into the calculator.
5. Click 'Calculate' to see your actual miles per gallon.

Why This Matters

Your vehicle's actual fuel economy often differs significantly from EPA ratings. Real-world MPG depends on your driving style, terrain, weather, tire pressure, and vehicle condition. Tracking your gas mileage helps you spot problems early - a sudden drop in MPG often indicates maintenance issues like dirty air filters, underinflated tires, or engine problems. Regular tracking also helps you understand how your driving habits affect fuel costs.

• Monitor vehicle health - sudden MPG drops indicate potential problems
• Understand how driving habits affect fuel economy
• Verify if vehicle modifications actually improve efficiency
• Track seasonal variations in fuel economy
• Make informed decisions about vehicle maintenance

Worked Examples

Common Mistakes to Avoid

• Not filling the tank completely - partial fills give inaccurate MPG calculations.
• Using one tank's data as gospel - average several fill-ups for accurate baseline MPG.
• Comparing city driving MPG to highway ratings - they're very different scenarios.
• Forgetting that MPG varies seasonally - winter fuel, cold engines, and snow tires reduce efficiency.
• Not resetting the trip odometer at fill-up - guessing at miles driven leads to inaccurate results.