Fuel Consumption Calculator: Find Your Real Fuel Use and Cost
Fill up, drive, refill, then enter the distance and the fuel it took.
This fuel consumption calculator shows how much fuel your car really uses and what it costs you, whether you count in litres per 100 km, kilometres per litre, or miles per gallon. Enter the distance you drove and the fuel it took to refill, and you get your fuel consumption in every common unit and the cost per kilometre or mile in one step. The other tabs price a trip before you leave, tell you how far a full tank will take you, and compare two cars side by side, so one page covers the questions most drivers ask about fuel. Whether you call it a fuel economy calculator or a fuel efficiency calculator, it runs the same maths on your own numbers.
Why is Fuel Consumption?
Fuel consumption is the amount of fuel a vehicle burns to cover a set distance. Most countries measure it in litres per 100 kilometres (L/100km), where a lower number is better, while South Asia uses kilometres per litre (km/L), and the US uses miles per gallon (MPG), where a higher number is better. A car using 8 L/100km burns 8 litres every 100 km, which equals 12.5 km/L or about 29 US MPG
How to Use This Fuel Consumption Calculator
The calculator has four tabs, and each one answers a different question about your fuel. Pick your country’s currency at the top, choose the tab that fits, and enter your numbers in the units you already use. Results update as you type, and the Print / PDF button saves your result as a one-page report you can print or keep.
- Fuel Consumption: enter the distance you drove and the fuel you used to get your real L/100km, km/L, US MPG, and UK MPG together, with a colour meter that shows whether your figure is good, average, or high.
- Trip Cost: enter a distance, your car’s fuel economy, and the fuel price to see the fuel needed, the total cost, and the cost per person.
- Fuel Range: enter your tank size and fuel economy to find how far you can drive on a full tank and what a fill-up costs.
- Compare Cars: enter two fuel economy figures and your yearly distance to see which car costs less to run and how much you save over one and five years.
Every tab works in kilometres or miles, litres, US gallons, or UK gallons, and in the currencies most drivers here use, from US, Canadian, and Australian dollars to pounds, euros, rupees, rand, and dirhams, so you can use the figures straight from your fuel receipt.
How to Calculate Fuel Consumption
You only need two numbers to work out fuel consumption: the distance you drove and the amount of fuel you used to cover it. The formula you apply depends on the unit you want, and the four below cover almost every car on the road.
Fuel Consumption in L/100km
Divide the litres used by the kilometres driven, then multiply by 100. If you drove 520 km and refilled with 41.6 litres, your car uses 41.6 ÷ 520 × 100 = 8.0 L/100km, and our L/100km calculator runs this formula on its own.
Kilometres per Litre
Divide the kilometres driven by the litres used. Covering 480 km on 32 litres gives 480 ÷ 32 = 15 km/L, and if km/L is the only unit you need, our car average calculator works it out on its own.
Miles per Gallon
Divide the miles driven by the gallons used. Driving 330 miles on 11 gallons gives 330 ÷ 11 = 30 MPG, and our MPG calculator walks through the same method for US drivers in more detail.
Fuel Consumption per Kilometre
To see how many litres of petrol or diesel your car burns per km, divide your L/100km figure by 100. A car using 8 L/100km burns 0.08 litres per kilometre, so a 50 km round trip to work uses about 4 litres.
How to Measure Your Car’s Real Fuel Consumption
The most accurate way to find your car’s real fuel consumption is the full tank method, because it uses fuel you actually paid for on roads you actually drive. It takes one full tank of normal driving and about a minute of maths.
Step 1. Fill the tank until the pump clicks off, then reset your trip meter to zero.
Step 2. Drive as you normally would until the tank is at least half empty.
Step 3. Fill up again at the same pump if you can, and note the litres or gallons it took.
Step 4. Enter the trip meter reading and the fuel added into the Fuel Consumption tab above.
Repeat it over two or three tanks and take the average, since one tank of mostly highway or mostly city driving can move the result by 10 to 20 percent. If you track your fuel in US terms, the gas mileage calculator also turns your result into a yearly fuel bill.
How to Calculate Diesel Consumption
Diesel consumption uses exactly the same formulas as petrol, so the calculator works for diesel cars, pickups, vans, and buses without any change. A diesel car using 5.5 L/100km burns 0.055 litres per km, which works out to about 18.2 km/L. Heavy trucks sit much higher, and a loaded truck using 35 L/100km burns 0.35 litres per km, or 280 litres over an 800 km haul. For trucks, the truck fuel calculator adds load and route to the estimate.
From Fuel Consumption to Fuel Cost
Once you know your fuel consumption, the cost of any trip takes one more step: multiply the fuel you need by the price per litre or gallon. A 450 km trip in a car using 7.5 L/100km needs 33.75 litres, and at 1.80 a litre that trip costs 60.75 in your local currency. In US terms, a 300 mile drive at 28 MPG uses 10.71 gallons, which comes to $37.50 at $3.50 a gallon, or 12.5 cents per mile.
For a full road trip with stops and shared costs, the trip fuel calculator goes further, and the fuel cost calculator prices a single drive in a few clicks. To turn your daily driving into a monthly budget, use the monthly fuel cost calculator.
How Far Can You Drive on a Full Tank?
Your fuel range is your tank size divided by your fuel consumption, and the Fuel Range tab works it out for you. A 50 litre tank in a car using 7 L/100km gives about 714 km on paper, and a 14 gallon tank at 28 MPG gives about 392 miles. Plan your next stop at around 90 percent of that figure, since the last few litres are hard to reach and the fuel gauge is rarely exact near empty.
Is Your Fuel Consumption Good, Average, or High?
The colour meter under your result places your car on a simple scale built for regular petrol cars. Below 7 L/100km (above 14.3 km/L or 33 US MPG) shows green for good, 7 to 10 L/100km shows yellow for average, and anything above 10 L/100km (below 10 km/L or 23.5 US MPG) shows red for high. A pickup, a large SUV, or a car that mostly sits in city traffic can land in the red and still be normal for its class, so read the meter as a quick check against a typical car.
For typical figures by vehicle type, from small hatchbacks to hybrids and pickups, see our guide to what counts as good fuel economy. If your figure comes from a source that uses a different unit, the fuel unit converter switches it before you compare.
Find Your Car’s Fuel Consumption by Make and Model
If you do not know your car’s figure yet, start with the official rating for your make and model. US drivers can look it up on fueleconomy.gov, run by the EPA and the US Department of Energy, while buyers in Europe and the UK see a WLTP figure in the brochure. Real-world driving usually lands 10 to 20 percent worse than these lab results, so use the official number for planning, then measure your own with the full tank method once you have a tank of real driving behind you.
What Affects Your Fuel Consumption
Driving style has the biggest effect, since hard acceleration and braking can lower fuel economy by 15 to 30 percent at highway speeds and by 10 to 40 percent in stop-and-go traffic, according to the US Department of Energy’s driving tips. Speed matters next, because fuel economy drops quickly above about 80 km/h (50 mph) as air resistance climbs.
Weather and load play a part too. Running the air conditioning in very hot weather can cut fuel economy by more than 25 percent on short trips, and in cold weather city fuel economy falls by about 15 percent. Every extra 45 kg (100 lb) in the car costs about 1 percent, a roof cargo box can cost 6 to 17 percent on the highway, and towing a trailer can cost 20 to 40 percent, which our towing calculator shows for your own trailer weight.
How to Reduce Fuel Consumption
Smooth driving saves the most fuel, so ease onto the accelerator, look ahead, and let the car roll to a stop instead of braking late. Holding a steady, moderate speed on the highway cuts fuel use on every long drive, and our guide to the best speed for fuel economy shows where the savings start. Switching the engine off during long stops saves fuel that covers no distance at all, as the idle fuel calculator shows.
Keep your tyres at the pressure printed inside the driver’s door, since correct tyre pressure can improve fuel economy by up to 3 percent, and take off an empty roof rack or box between trips. Regular servicing with a clean air filter and fresh oil keeps your car close to its best figure over time.
More Fuel Calculators
Find your real fuel economy with the Gas Mileage Calculator, MPG Calculator, L/100km Calculator, or km/L Calculator. Plan your costs with the Fuel Cost Calculator, Trip Fuel Calculator, Monthly Fuel Cost Calculator, and Cost Per Mile Calculator, and switch units with the Fuel Unit Converter.
For work vehicles, use the Truck Fuel Calculator, Fleet Fuel Calculator, Towing Fuel Calculator, and Tractor Fuel Calculator. For everything else, try the EV vs Petrol Calculator, Boat Fuel Calculator, Generator Fuel Calculator, and Idle Fuel Calculator.
Frequently Asked Questions:
Methodology
Every result uses the standard fuel consumption formulas shown on this page, with exact conversions between units: 1 US gallon equals 3.785 litres, 1 UK gallon equals 4.546 litres, and 1 mile equals 1.609 km. Benchmark ranges and fuel saving figures come from fueleconomy.gov and US Department of Energy guidance, and your results stay in your browser, with nothing stored or sent anywhere. Reviewed by the FuelConsumptionCalc Editorial Team.
Last updated September 2026.