There are many reasons for wanting to know your gas tank capacity. One of the most common reasons people want to find out this information is that they believe the gas station is charging them for too much gas. Another reason is that people may want to calculate the number of fill-ups they need for a road trip. Whatever your reason for wanting to find out the capacity of your gas tank, the process is very simple.
Check your owner's manual. The owner's manual will always list the average capacity of a gas tank for your specific model and make of car. However, be aware that this number is still only an estimate and can vary from the actual tank capacity by as much as three percent.
Measure your gas tank size. To do this you will need to get under the car and physically measure the size of your tank with a tape measure. Measure the height, width and length of the tank in inches. Once you have the measurements, go to the URL Brokeboats.com/tankcapacity.html and enter the data into the appropriate fields. Click "calculate" and the site will provide you with your tank capacity in gallons.
Run your tank completely out of gas and then see how much fuel it takes to refill it. The best way to do this is to first fill up a 1-gallon container of gas at the gas station. Keep the gallon of gas in your car while you drive around. Drive until your car is completely out of gas, making sure that a gas station is nearby when you run out. Pour the gallon of gas into the tank and drive the rest of the way to the gas station. Pump gas from the station into your tank until your tank is full. The number of gallons that it takes to fill up your tank is the capacity of your tank minus one gallon or less.
