Fuel Cost Calculator

How Trip Fuel Cost Is Calculated

Divide the distance by your fuel economy to find how much fuel the trip burns, then multiply by the fuel price:

US units: Cost = (Miles ÷ MPG) × Price per Gallon

Metric: Cost = (km ÷ 100) × L/100km × Price per Liter

A 300-mile trip in a 30 MPG car at $3.50 per gallon uses 10 gallons and costs $35. Split between four people, that's $8.75 each.

MPG vs. L/100km

The two systems run in opposite directions: higher MPG is better, while lower L/100km is better. To convert, divide 235.21 by either figure — 30 MPG ≈ 7.8 L/100km, and 5 L/100km ≈ 47 MPG. If your dashboard shows km/L instead, multiply by 2.352 to get MPG.

Ways to Cut Your Fuel Bill

• Tire pressure: under-inflated tires cost up to 3% in fuel economy.
• Smooth driving: aggressive acceleration and braking can burn 15-30% more fuel on the highway.
• Speed: economy typically drops sharply above 50-55 mph; every 5 mph over is roughly like paying $0.20+ more per gallon.
• Weight and drag: remove roof boxes and heavy cargo you don't need.
• Carpool: the cheapest gallon is the one split four ways.

Planning a bigger picture budget? Pair this with our loan calculator for car payments or the percentage calculator for quick comparisons.

Frequently Asked Questions

How do I calculate the fuel cost of a trip?

Divide the trip distance by your vehicle's fuel economy to get gallons (or liters) used, then multiply by the fuel price. A 300-mile trip at 30 MPG and $3.50/gallon costs 10 gallons × $3.50 = $35.

How do I convert MPG to liters per 100 km?

Divide 235.21 by the MPG figure. 30 MPG equals about 7.8 L/100km. This calculator accepts either unit directly — just switch the units selector.

How can I reduce fuel costs?

Keep tires properly inflated, avoid aggressive acceleration, remove roof racks, and maintain steady highway speeds — together these can improve fuel economy 15-30%. Carpooling splits the cost directly.

Should I use city or highway MPG?

Use the combined figure for mixed trips, highway MPG for long interstate drives, and city MPG for stop-and-go routes. Real-world economy is usually a little below the EPA sticker numbers.