Fuel Cost Calculator

How to Estimate Fuel Costs for a Trip

Estimating fuel costs for a road trip requires three key inputs: the total distance you plan to drive, your vehicle's fuel efficiency, and the current fuel price. For US units, divide the distance in miles by your vehicle's MPG to get gallons needed, then multiply by the price per gallon. For metric, multiply the distance in kilometers by the L/100km rating divided by 100 to get liters needed, then multiply by the price per liter. This calculator handles both systems instantly.

Keep in mind that your actual fuel consumption may vary due to driving conditions, traffic, weather, vehicle load, and driving habits. Always add a 10-15% buffer to your budget for unexpected detours or price increases. For multi-vehicle trips or caravans, multiply the total fuel cost by the number of vehicles.

MPG vs. L/100km Explained

MPG (miles per gallon) is the standard fuel efficiency measure used in the United States. It tells you how many miles a vehicle can travel on one gallon of fuel. A higher MPG number means better fuel economy. For example, a car that gets 30 MPG can travel 30 miles on one gallon of gasoline.

L/100km (liters per 100 kilometers) is the standard measure used in Canada, the UK, Europe, Australia, and most other countries. It tells you how many liters of fuel are consumed to travel 100 kilometers. A lower L/100km number means better fuel economy. For example, a car that consumes 8 L/100km uses 8 liters to travel 100 kilometers.

Both measures express the same thing — fuel efficiency — but in inverse terms. To convert between them: MPG = 235.21 / L/100km and L/100km = 235.21 / MPG. For UK MPG (imperial gallons), use 282.48 instead of 235.21.

Average Fuel Economy by Vehicle Type

Vehicle Type	MPG (US)	L/100km	Annual Fuel Cost (15,000 mi)
Compact Car	30 - 40	5.9 - 7.8	$1,300 - $1,750
Sedan	25 - 35	6.7 - 9.4	$1,500 - $2,100
SUV	18 - 28	8.4 - 13.1	$1,875 - $2,900
Truck / Pickup	15 - 22	10.7 - 15.7	$2,400 - $3,500
Hybrid	45 - 55	4.3 - 5.2	$950 - $1,160
Electric (MPGe)	100 - 130	1.8 - 2.4	$400 - $520 (electricity)

Actual fuel economy depends on driving habits, maintenance, and conditions. The EPA estimates are a useful baseline, but real-world numbers can vary by 10-20%.

Factors That Affect Fuel Economy

• Speed: Fuel efficiency peaks around 50-55 mph. Every 5 mph above 60 mph is equivalent to paying an extra $0.20-$0.30 per gallon.
• Vehicle Maintenance: Dirty air filters, worn spark plugs, and old engine oil can reduce fuel economy by 10-15%. Under-inflated tires increase rolling resistance and decrease MPG by up to 3%.
• Air Conditioning: Using AC at highway speeds reduces fuel economy by about 5-10%. At low speeds, rolling down windows is more efficient; at highway speeds, AC is better due to aerodynamic drag from open windows.
• Excess Weight: Every 100 pounds of extra weight reduces MPG by about 1%. Roof racks and cargo boxes create aerodynamic drag that can reduce highway fuel economy by 5-25%.
• Terrain and Traffic: Hilly terrain, stop-and-go traffic, and rough roads significantly increase fuel consumption. City driving typically uses 20-40% more fuel than highway driving.
• Cold Weather: Fuel economy can drop 10-20% in winter due to thicker engine oil, longer warm-up times, and increased use of heaters and defrosters.

Fuel Saving Tips

• Drive smoothly and anticipate traffic. Avoid rapid acceleration and hard braking. Gentle driving can improve fuel economy by 15-30% on highways and 10-40% in stop-and-go traffic.
• Maintain proper tire pressure. Check your tire pressure monthly and keep it at the manufacturer's recommended PSI. Under-inflated tires increase rolling resistance and lower fuel efficiency.
• Reduce highway speed. Reducing your speed from 65 mph to 55 mph can improve fuel economy by up to 15%. Use cruise control to maintain a constant speed on flat highways.
• Remove excess weight and drag. Take unnecessary items out of your trunk and remove roof racks or cargo boxes when not in use. Even an empty roof rack can reduce MPG by 5% at highway speeds.
• Combine errands into one trip. A warm engine is more efficient than multiple cold starts. Plan your route to minimize distance and avoid peak traffic hours.
• Use the recommended motor oil. Using the manufacturer's recommended viscosity grade can improve fuel economy by 1-2%. Look for "Energy Conserving" oil labels.
• Avoid excessive idling. Idling gets 0 MPG. Turn off the engine if you expect to be stopped for more than 60 seconds. Restarting uses less fuel than idling.
• Use overdrive and high gears. Driving in the highest possible gear reduces engine RPM and saves fuel. On the highway, use overdrive if your vehicle has it.
• Plan your route. Use GPS navigation to find the most fuel-efficient route. Highway driving is generally more efficient than city driving with frequent stops.
• Keep your vehicle tuned. Regular maintenance — including replacing air filters, spark plugs, and oxygen sensors — keeps your engine running at peak efficiency.

Beyond Fuel: Other Trip Costs to Budget

Fuel is typically the largest variable expense on a road trip, but a complete budget should account for several other costs. Tolls and parking fees can add $10-$50 per day depending on your route. Meals and snacks for a family of four can run $60-$120 per day. Accommodations range from $80-$200 per night for hotels or $30-$50 for campgrounds. Vehicle wear and tear including oil changes, tire wear, and potential repairs should be factored in at roughly $0.05-$0.10 per mile. Emergency funds for unexpected breakdowns or detours are also wise. Using a Moving Cost Calculator alongside this fuel cost calculator gives you a complete financial picture before you hit the road.

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