Free Fuel Cost Calculator

The Fuel Cost Calculator is a free online tool that estimates trip fuel costs based on distance, fuel efficiency, and current fuel prices.

Yes, it is completely free with no registration required. All calculations happen client-side in your browser.

Yes, the Fuel Cost Calculator supports both miles per gallon (MPG) and liters per 100 kilometers for fuel efficiency input.

Absolutely. The Fuel Cost Calculator processes everything client-side in your browser. No data is uploaded to or stored on any server. Your content remains private on your device at all times.

Yes, the Fuel Cost Calculator is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.

No account or registration is needed. Simply open the Fuel Cost Calculator in your browser and start using it immediately. There are no sign-up walls or usage restrictions.

The Fuel Cost Calculator uses industry-standard formulas and algorithms to ensure accurate results. However, for critical financial or medical decisions, always consult a qualified professional.

Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.

The Fuel Cost Calculator works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.

Trip fuel cost comes from three numbers: distance, your vehicle's fuel efficiency, and the price you pay per gallon or liter. First find the fuel needed by dividing distance by efficiency — for example, a 300-mile drive at 30 MPG burns 10 gallons. Then multiply that fuel by the price per unit: 10 gallons at $3.50 equals $35.00. In metric, divide distance by 100 and multiply by your L/100km figure to get liters, then multiply by price per liter. The calculator does all of this instantly and also shows cost per mile and per kilometer, so you can compare routes at a glance. Toggle round-trip to double the distance, or set a passenger count to split the bill evenly. Enter your distance, efficiency, and fuel price to see the full breakdown.

MPG and L/100km are inverse measures, so you divide rather than multiply. The standard conversion uses the constant 235.215: to go either direction, divide 235.215 by your number. So 30 MPG becomes 235.215 / 30, or about 7.84 L/100km, and 8 L/100km becomes 235.215 / 8, or about 29.4 MPG. The constant bundles together the gallon-to-liter (3.78541) and mile-to-kilometer (1.60934) factors. Note that this assumes US gallons; UK imperial gallons are larger, so an imperial MPG figure looks better than it really is. Because the two scales run in opposite directions, a lower L/100km means a more efficient car while a higher MPG does — that flip trips a lot of people up. This calculator accepts MPG, L/100km, or km per liter directly, so you can enter whichever your car reports without converting by hand.

Usually electric, but it depends on local rates. A gas car's per-mile cost is fuel price divided by MPG, while an EV's is your electricity rate per kWh times its consumption (often 3 to 4 miles per kWh). At a typical home rate, charging an EV frequently costs the equivalent of paying around a dollar per gallon, which beats most gas vehicles — but expensive public fast-charging or pricey grid electricity can narrow or erase that gap. Emissions differ too: the calculator estimates EV carbon against the US grid average of about 0.386 kg of CO2 per kWh, so a clean grid makes an EV far greener while a coal-heavy one less so. Use the EV vs Gas mode to enter your real electricity rate and fuel price side by side and see which costs less per trip and per year.

Burning one gallon of gasoline releases roughly 8.89 kilograms of CO2 — far more than the gallon weighs, because each carbon atom combines with oxygen from the air during combustion. Diesel is denser and emits about 10.16 kg per gallon, while E85 ethanol blend produces less per gallon since much of its energy comes from plant-based ethanol. These EPA-style emission factors let the calculator turn any trip into an estimated carbon footprint: multiply the fuel you burn by the factor for your fuel type. For electric trips it instead uses the US grid average of about 0.386 kg of CO2 per kWh, which is why an EV's footprint varies with local electricity sources. These figures are well-established averages meant for planning and awareness, not regulatory reporting. Enter a trip and your fuel type to see fuel volume, cost, and estimated emissions together.

The savings grow faster than the MPG numbers suggest, because cost scales with the inverse of efficiency. Going from 20 to 40 MPG halves your fuel use and your fuel bill — a car at 40 MPG costs half as much to fuel over the same distance as one at 20. But the same 20-MPG jump matters less higher up: 30 to 50 MPG cuts cost by only about 40 percent, not half. That is why upgrades from a thirsty vehicle pay off most. To put real money on it, multiply your annual mileage by fuel price, then divide by each car's MPG and compare the totals. The Compare Cars mode lines up two or more vehicles over the same trip, and Projections turns your weekly or yearly mileage into projected monthly and annual costs so you can judge whether a switch pays for itself.