How is car fuel cost calculated?

[VanSamantha]

First, fill up the fuel tank (until the pump nozzle clicks off), reset the trip meter to zero. After the second fill-up (also until the nozzle clicks off), divide the amount of fuel added the second time by the kilometers driven since the trip meter was reset to get the actual fuel consumption. Then multiply by the unit price of gasoline. Below is the calculation method for gasoline cost: 1. Fill up the fuel tank until the pump nozzle clicks off, and reset the trip meter to zero. Try to drive as many kilometers as possible, as too few will result in inaccurate calculations. The next time you refuel, fill up until the nozzle clicks off again. Then, divide the liters of fuel added by the kilometers shown on the trip meter, move the decimal point two places to the right, and this number will be the car's fuel consumption per 100 kilometers. 2. If the car is equipped with an onboard computer, even better, as the instant fuel consumption and average fuel consumption will be automatically displayed on the dashboard screen.

[AryaMarie]

I usually calculate fuel costs by keeping track of two numbers: how many liters of fuel I added and how many kilometers I drove. For example, last time I added 40 liters of fuel and drove 500 kilometers, so the fuel consumption per 100 kilometers was 8 liters. Multiply this number by the latest fuel price, like the current price of 92-octane gasoline at 7.5 yuan per liter, and it costs about 0.6 yuan per kilometer. However, my old SUV has relatively high fuel consumption. If it were my colleague’s hybrid car, it would only consume 4 liters per 100 kilometers, saving half the money under the same road conditions. The size of the fuel tank also matters. My 60-liter tank costs 450 yuan to fill up, enough to drive over 700 kilometers, but in summer when the air conditioning is on, the mileage drops by 10%.

[DiLaura]

Tracking fuel consumption with a mobile app is super convenient. Every time I refuel, I take photos of the odometer and fuel amount, and the app automatically calculates the cost per kilometer. Last week's highway data was quite interesting: at 100 km/h, the consumption was 6.8L per 100km, but it rose to 7.9L when speeding up to 120 km/h. Tire pressure also affects fuel efficiency – once when the pressure was below 2.0, the consumption was 0.5L higher than normal. The most surprising finding was the comparison between opening windows and using AC: below 80 km/h, opening windows saves fuel, but above 80 km/h, using AC becomes more economical as wind resistance significantly increases fuel consumption.

[StKayden]

Don't just rely on the displayed fuel consumption for cost calculation. My car's display is always about 0.6L lower than the actual consumption, so it's better to calculate based on actual refueling amounts. Different road conditions make a huge difference: urban traffic can easily push it over 10L/100km, while suburban highways can bring it down to 6L. Also pay attention to fuel price fluctuations—I always check prices every Friday and choose gas stations with discounts nearby, saving hundreds a year. Avoid refueling at noon during high temperatures; with gasoline's expansion coefficient of 0.0012, you actually get less fuel when refueling in hot weather.

[VonCassidy]

Here's a practical trick: Run your tank until the fuel light comes on, then fill up with 200 yuan worth of gas and note how many kilometers you can drive on that tank. For example, my car can go 330 km on 200 yuan, which works out to 0.6 yuan per kilometer. However, fuel consumption increases in winter; at -10°C, the range drops by about 15%. Timing your refueling also matters—it's best to fill up in the cool early morning when gasoline density is higher, making it more cost-effective. In the long run, changing the engine oil every 5,000 km during maintenance can reduce fuel consumption by about 4%, which is way more valuable than saving a bit on gas.