Write an article based on this "Calculate fuel costs by writing down the number of miles or kilometers on the odometer when the fuel tank is nearly empty. Fill the tank when it is near empty. Refill the tank when it is near empty again and write down the number of gallons or liters it took to fill. Check the odometer again at refilling and subtract the old number on the odometer from the new number to see how far you drove. Divide the number of miles or kilometers you drove by the number of gallons or liters it took to refill your tank. Divide the distance driven in a month by the miles or kilometers per gallon or liter. Multiply the total amount of fuel per month you burn by the cost of a gallon or liter of gasoline to get your monthly fuel costs."
Do not top off the tank. Do not top off when refilling. Write down the difference between the two odometer readings. If the number was 30,000 miles (48,280 km) when you filled the tank the first time and 30,300 (48,763 km) when you refilled, you drove 300 miles (482.8 km) on 1 tank of gas. For example, if you drove 300 miles (482.8 km) and burned 15 gallons (56.78 liters) of gasoline, your vehicle got about 20 miles per gallon (8.5 km per liter). (If your car has 30,000 miles [48,280 km] and is 40 months old, you drive about 750 miles [1,207 km] per month.) In this hypothetical example, divide 750 (1,207 km) by 20 gallons (75.7 liters) to get the number of gallons or liters you burn per month: 37.5 gallons (142 liters). If gas costs $4 per gallon ($1.05 per liter), you spend $128 per month on fuel, or 17 cents per mile (10 cents per km).