Fuel Consumption Calculator

Fuel cost is calculated using three core inputs: distance traveled, your vehicle's fuel economy, and the unit price of fuel. First, divide your total trip distance by your vehicle's fuel economy rating to find the total fuel consumed (e.g., 300 miles ÷ 30 MPG = 10 gallons). Then, multiply total fuel consumed by the price per gallon or liter (e.g., 10 gallons × $3.50/gal = $35.00 total fuel cost). Our online calculator performs instant unit conversions between US MPG, UK Imperial MPG, L/100km, km/L, and global currencies automatically.

Fuel economy is measured differently depending on the country. In the US, miles per US gallon (MPG US) is standard. In the UK, Imperial miles per gallon (MPG UK) is used. In Europe, Canada, and Australia, Liters per 100 kilometers (L/100km) is standard. In Asia and South America, kilometers per liter (km/L) is common. A US liquid gallon is 3.785 liters, whereas an Imperial UK gallon is 4.546 liters (20.09% larger). A vehicle rated at 40 MPG UK achieves roughly 33.3 MPG US. Our calculator normalizes all four units simultaneously so you can evaluate global vehicle ratings side by side.

To split gas expenses fairly on road trips or carpools, enter the total number of travelers in the 'Passengers' field inside our calculator. The calculator computes the total trip fuel expense and divides it equally per person. For example, a 600-mile road trip costing $90 in gas split among 4 passengers results in exactly $22.50 per person.

EPA ratings are measured under controlled laboratory conditions on chassis dynamometers at room temperature with zero wind resistance. Real-world fuel economy is typically 10% to 25% lower due to aggressive acceleration, payload weight, roof racks, low tire pressure, extreme winter temperatures, hilly terrain, and prolonged engine idling.

Use the tank-fill method: Fill your fuel tank completely at a gas station until the pump nozzle clicks off automatically, and record your exact odometer reading. Drive normally until your tank is below 1/4 full, then refill completely again at the same pump if possible. Note the exact gallons or liters pumped and your new odometer mileage. Subtract starting mileage from ending mileage to get distance driven, then divide miles driven by gallons used for MPG (or divide liters used by kilometers driven and multiply by 100 for L/100km).

Yes. Rapid acceleration, high-speed highway cruising above 65 mph, and frequent hard braking reduce highway fuel mileage by up to 30% and city mileage by 10% to 40%. Aggressive driving burns extra fuel rapidly, adding $0.50 to $1.00 in wasted expense per gallon equivalent.

A standard passenger car burns 0.2 to 0.5 gallons (0.8 to 1.9 liters) of fuel per hour while idling. Large V8 trucks and commercial diesel rigs burn 0.5 to 1.0 gallon per hour idling. Idling gets 0.0 MPG and increases engine oil degradation.

Towing a travel trailer, camper, boat, or enclosed cargo box creates severe aerodynamic drag and increases vehicle weight load. Towing typically reduces fuel economy by 30% to 50%, causing a truck that normally gets 20 MPG to drop to 10–12 MPG.

At highway speeds above 45 mph, open windows create significant aerodynamic turbulence and drag, which consumes more fuel than running the vehicle's air conditioner. At city speeds below 45 mph, opening windows is more fuel-efficient than using AC.

Tires naturally lose about 1 PSI per month and 1 PSI for every 10°F drop in ambient temperature. Under-inflated tires increase rolling resistance, reducing fuel economy by 0.2% for every 1 PSI drop below the manufacturer's recommended tire pressure listed on the driver-side door jamb.

No. Unless your vehicle's engine requires or recommends high-octane fuel (such as high-compression or turbocharged engines), using premium gas provides zero additional horsepower, zero extra MPG, and simply increases fuel costs by 20% to 30%.

For most passenger vehicles, fuel efficiency peaks between 45 mph and 55 mph. Above 50 mph, fuel efficiency drops off sharply due to aerodynamic drag; driving at 75 mph consumes approximately 15% to 20% more fuel than driving at 60 mph.