Gas Calculator
Calculate the total gas cost for your trip. Enter the distance, your vehicle's fuel efficiency, and the current gas price to estimate fuel needed, total cost, and cost per mile or kilometer. Perfect for road trips, commuting, and budget planning.
How to Calculate Gas Cost
The gas cost for a trip depends on three main factors: the distance of your journey, your vehicle's fuel efficiency, and the current gas price. The calculator uses simple formulas to give you accurate estimates:
Imperial (miles, gallons):
Gas Needed = Distance (miles) ÷ Fuel Efficiency (MPG)
Total Cost = Gas Needed × Price per Gallon
Cost per Mile = Total Cost ÷ Distance
Metric (km, liters):
Gas Needed = Distance (km) × Fuel Efficiency (L/100km) ÷ 100
Total Cost = Gas Needed × Price per Liter
Cost per km = Total Cost ÷ Distance
For example, a 300-mile trip with a vehicle that gets 25 MPG and gas at $3.50/gallon:
- Gas Needed = 300 ÷ 25 = 12 gallons
- Total Cost = 12 × $3.50 = $42.00
- Cost per Mile = $42.00 ÷ 300 = $0.14/mile
Why Use This Gas Calculator?
- Accurate Estimates: Get precise gas cost calculations for any trip.
- Dual Unit Systems: Switch between imperial (miles, gallons) and metric (km, liters).
- Multiple Currencies: Supports USD, EUR, GBP, and more.
- Round Trip & Fleet Options: Account for round trips and multiple vehicles.
- Free & Private: No registration, no data storage.
Tips to Save on Gas Costs
- Drive Smoothly: Avoid rapid acceleration and hard braking.
- Maintain Your Vehicle: Keep tires properly inflated and engines tuned.
- Reduce Speed: Fuel efficiency drops significantly at speeds above 60 mph (100 km/h).
- Remove Excess Weight: Clear out unnecessary items from your vehicle.
- Plan Your Route: Avoid traffic and take the most direct path.
- Use Gas Apps: Find the cheapest gas stations along your route.
❓ Gas Calculator FAQ
How do I calculate gas cost for a trip?
Multiply the distance by your vehicle's fuel consumption rate, then multiply by the gas price. The calculator does this automatically — just enter your distance, fuel efficiency, and gas price.
What is MPG and how is it used?
MPG (Miles Per Gallon) measures how far your vehicle can travel on one gallon of gas. It's used in the imperial system to calculate fuel consumption. The higher the MPG, the more fuel-efficient your vehicle is.
What is L/100km and how is it used?
L/100km (Liters per 100 kilometers) measures how much fuel your vehicle uses to travel 100 kilometers. It's used in the metric system. The lower the L/100km, the more fuel-efficient your vehicle is.
How do I convert MPG to L/100km?
To convert MPG to L/100km, divide 235.215 by the MPG value. For example, 25 MPG = 235.215 ÷ 25 = 9.41 L/100km.
How do I convert L/100km to MPG?
To convert L/100km to MPG, divide 235.215 by the L/100km value. For example, 8.5 L/100km = 235.215 ÷ 8.5 = 27.67 MPG.
What is the average gas cost per mile?
The average gas cost per mile varies by vehicle, gas prices, and driving conditions. As of 2025, the average is about $0.15-$0.20 per mile for gasoline vehicles in the US. This calculator gives you a personalized estimate.
How does driving speed affect gas costs?
Fuel efficiency typically decreases at speeds above 60 mph (100 km/h). Every 5 mph over 60 mph is like paying an additional $0.20-$0.30 per gallon. Driving at moderate speeds can significantly reduce your gas costs.
What is the most fuel-efficient speed?
Most vehicles achieve their best fuel efficiency between 45-60 mph (70-95 km/h). Driving at these speeds can improve your MPG by 10-20% compared to highway speeds.
How does vehicle weight affect fuel consumption?
Every 100 pounds (45 kg) of extra weight can reduce fuel efficiency by 1-2%. Removing unnecessary items from your trunk can save you money on gas over time.
What is the difference between city and highway MPG?
City MPG is lower because of frequent stops, starts, and idling. Highway MPG is higher because you maintain a steady speed. Use the combined MPG for a realistic estimate of your gas costs.
How do I calculate gas cost for a round trip?
Simply double the distance of your one-way trip. The calculator has a "Round Trip" option that does this automatically for you.
How do I calculate gas cost for multiple vehicles?
Enter the number of vehicles in the advanced options. The calculator will show the total cost and the cost per vehicle, making it easy for fleet planning or group trips.
How does tire pressure affect gas costs?
Under-inflated tires can increase fuel consumption by up to 3%. Keeping your tires properly inflated can save you money and improve safety.
What is the difference between gasoline and diesel fuel costs?
Diesel fuel is often more expensive than gasoline, but diesel engines are typically more fuel-efficient (15-30% better MPG). Use this calculator to compare gas costs for different vehicle types.
How can I reduce my gas consumption?
Drive smoothly, maintain your vehicle, reduce speed, remove excess weight, plan your route, and avoid aggressive driving. These habits can reduce your fuel consumption by 10-30%.
What is the difference between premium and regular gasoline?
Premium gasoline has a higher octane rating and is recommended for high-performance vehicles. For most cars, regular gasoline is sufficient. Using premium fuel in a car that doesn't require it won't improve performance or fuel economy.
How do I calculate gas cost for an electric vehicle?
For electric vehicles, you would calculate cost per mile using electricity rates instead of gas prices. This calculator is designed for gasoline and diesel vehicles. Try our EV Cost Calculator for electric vehicles.
Is this calculator accurate for real-world driving?
This calculator provides estimates based on standard fuel consumption calculations. Actual gas costs can vary based on driving conditions, traffic, weather, and individual driving habits. Use it as a planning tool for budgeting your trips.
What is the best way to find cheap gas?
Use gas price apps like GasBuddy, Waze, or Google Maps to compare prices at stations along your route. Gas prices can vary by up to $0.50 per gallon between stations, so shopping around can save you money.