How to Calculate a Car's Fuel Consumption?
3 Answers
The method to calculate a car's fuel consumption: First, fill the fuel tank completely, reset the odometer or record the mileage information. After driving for a period, refuel until the pump automatically stops. Divide the fuel consumed by the distance traveled between the two refueling stops, then multiply by 100 to get the actual fuel consumption. Subsequently, you can calculate the mileage and fuel consumption based on this rule. The fuel consumption per 100 kilometers is equal to the volume of fuel (in liters) divided by the distance the car can travel (in kilometers) on that amount of fuel, multiplied by 100. Constant-speed fuel consumption refers to the fuel economy indicator when a car is driving at a constant speed on a good road surface. Since constant-speed driving is a basic operating condition for cars on highways, and this type of fuel consumption is easy to measure, it is widely adopted.
I’ve always driven city cars, and calculating fuel consumption is simple and practical. First, fill up the tank until the pump clicks off, and note the odometer reading. After driving normally for 100–200 kilometers, return to the same gas station and refill the tank to full, then measure the amount of fuel added this time. Divide the fuel amount by the kilometers driven, then multiply by 100 to get the fuel consumption in L/100km. I use this method once a month—it’s especially accurate and reliable, unlike the car’s onboard computer display, which sometimes fluctuates significantly. The key is to test under similar road conditions. For example, driving in the city multiple times will reveal the average fuel consumption, while highway or long-distance trips should be measured separately. Keeping records over time helps identify how habits affect consumption. I adjusted by braking less aggressively and saved a bit on fuel. Regular maintenance, like proper tire pressure, also improves efficiency.
Driving for over thirty years, calculating fuel consumption has become second nature to me. Before every long trip, I choose a starting point to fill up the tank and meticulously record the mileage. Upon reaching the destination, I repeat the process, measuring the fuel used divided by the distance traveled, then multiplying by 100. The L/100km unit is ideal for the metric system, easy to remember and use. It's more accurate when driving at a steady speed on highways, with minimal fluctuations. Experience has taught me that small tricks, like refueling in the early morning when the fuel temperature is stable, can minimize errors. As a side note, steep uphill sections or heavy traffic can result in higher readings, but taking multiple measurements under normal conditions will yield a reliable average. Developing this habit saves money, is eco-friendly, and helps in timely vehicle maintenance.
