⛽ Fuel Cost Calculator

Planning Your Fuel Budget

Fuel is often one of the largest variable expenses for vehicle owners — understanding exactly what each trip costs helps you budget accurately, make smarter transportation choices, and evaluate potential savings from fuel efficiency improvements. This calculator works with both MPG (miles per gallon, the U.S. standard) and L/100km (liters per 100 kilometers, used in Canada, Europe, Australia, and most of the world).

The calculation is straightforward. In MPG mode: Cost = (Distance ÷ MPG) × Price per Gallon. In L/100km mode: Cost = (Distance ÷ 100) × Consumption × Price per Liter. The cost per mile or kilometer helps you compare the true transportation cost across different vehicles, routes, and fuel price scenarios.

Understanding Fuel Efficiency Ratings

Fuel efficiency ratings tell you how far a vehicle travels per unit of fuel. Higher MPG or lower L/100km is more efficient:

• City vs Highway ratings: The EPA provides separate city, highway, and combined ratings for every vehicle. City driving (frequent stops, idle time) uses significantly more fuel per mile than highway driving (consistent speed, minimal braking). Real-world efficiency often falls between city and highway estimates depending on your driving conditions.
• Typical modern vehicle efficiency: Compact cars: 30–40 MPG; Mid-size sedans: 25–35 MPG; SUVs: 20–30 MPG; Trucks: 15–25 MPG; Full-size trucks: 12–20 MPG; Hybrid vehicles: 40–60 MPG; Electric vehicles: 100–140 MPGe equivalent.
• Your actual mileage vs EPA estimates: Real-world fuel economy typically runs 10–20% below EPA estimates depending on driving habits, climate, load, tire pressure, and vehicle condition. Track your own fuel economy using the odometer and fill-up records for the most accurate budgeting.

Practical Tips to Reduce Fuel Costs

• Drive at moderate speeds: Fuel efficiency typically peaks at 45–55 mph. Every 5 mph above 60 mph is roughly equivalent to paying $0.15–$0.30 more per gallon. Highway trips at 65 mph vs 75 mph can improve efficiency by 15–20%.
• Avoid jackrabbit acceleration: Aggressive acceleration burns disproportionately more fuel. Smooth, gradual acceleration maintains better efficiency and reduces brake wear.
• Maintain proper tire pressure: Each PSI below recommended pressure reduces efficiency by about 0.2%. Under-inflated tires can reduce MPG by 3–4%, cost you money on every tank, and wear tires unevenly.
• Reduce idle time: Idling gets 0 MPG. Modern fuel-injected engines use less fuel restarting than idling for more than 30–60 seconds. Turn off the engine during longer waits.
• Remove excess weight: Every 100 lbs of extra weight reduces fuel economy by about 1%. Remove cargo and roof racks when not in use.
• Use cruise control: Maintains a consistent speed more efficiently than human drivers, particularly on long flat highway stretches. Can improve highway efficiency by 5–14%.
• Plan efficient routes: Shorter isn't always faster or more efficient. Avoiding stop-and-go traffic (even if the highway route is slightly longer) often saves fuel.
• Maintain your vehicle: Dirty air filters reduce fuel economy by up to 10%. Worn spark plugs can reduce efficiency by 4–8%. Regular maintenance keeps your vehicle at its designed efficiency.
• Use the recommended fuel grade: Premium fuel in a standard vehicle provides no benefit — it's simply wasted money. Use the grade specified in your owner's manual.

Comparing Vehicle Fuel Costs

When deciding between vehicles, the fuel cost difference over 5 years can be significant. A vehicle that gets 25 MPG vs 35 MPG, driven 15,000 miles/year at $3.50/gallon: 25 MPG costs $2,100/year; 35 MPG costs $1,500/year — a $600/year difference, or $3,000 over 5 years. Over the ownership period, fuel efficiency often matters as much as purchase price.

Frequently Asked Questions

How do I convert between MPG and L/100km? The conversion formula is: L/100km = 235.21 / MPG. So 30 MPG ≈ 7.84 L/100km. Conversely: MPG = 235.21 / (L/100km). These are inversely proportional — as one increases, the other decreases.

How do I calculate my actual fuel economy? Fill your tank to full. Reset the trip odometer or note the mileage. Drive normally. When you refuel to full again, divide the miles driven by the gallons needed to refill. This gives your actual MPG for that tank, which you can average over several fill-ups for a realistic efficiency figure.

How does temperature affect fuel economy? Cold weather significantly reduces fuel economy — a 20°F day can reduce MPG by 15–24% compared to a 77°F day, partly because engines take longer to reach optimal operating temperature, partly because cold air is denser, and partly because winter-blend gasoline has slightly less energy than summer-blend. Air conditioning in hot weather reduces fuel economy by 5–25% depending on the vehicle and how hard the AC is working.