Calculating your gas mileage is easy. Follow these steps and you will be able to calculate your own gas mileage each time you fill up the tank. Here's how - we're going to figure out how many miles you drive between fill-ups, then we're going to figure out how much gas you used. Finally, we're going to do some really simple math and come up with a very accurate estimate of your gas mileage. All you'll need is a piece of paper, a simple calculator (the one in your cell phone will work fine), and a minute or two at the gas station right after you fill up.

Step 1: Put gas in your gas tank until it is full. Step 2: Push the trip odometer in your vehicle so that resets to zero. If you can't for whatever reason, then you can just write down the total mileage of your vehicle on the piece of paper. Step 3: Drive around normally until it's time to put gas in your car. Step 4: Put gas in your tank, filling it completely.

Step 5: Figure out how many miles you've driven since your last fill-up. You can look at your trip odometer for the answer, or you can figure out how far you've driven using the scrap of paper from step 2 and your calculator. Write down that mileage and go to the next step. NOTE: Keep in mind that most of the time, the number you write down in step 5 should be between 100-500 miles.

If you've driven a lot more or a lot less, there might be a problem with your math (or you're getting really good mileage). Step 6: Next you need to figure out how much gas you have used between fill-ups. To do this, all you have to do is to look at the pump. The number of gallons on the gas pump is how much gas you used between fill-ups. Write down the number of gallons with a few numbers after the decimal point on the piece of paper. Step 7: Now, on your calculator, divide the number of miles you drove between fill-ups by the number of gallons of gas you used (The number in Step 5 divided by the number in Step 6).

This equals your gas mileage! If you drive a truck or large SUV, gas mileage should be somewhere between 20 and 12. If you drive a large car or small SUV, gas mileage should be somewhere between 25 and 18. If you drive a mid-size or compact car, gas mileage should be somewhere between 35 and 25.

Gas mileage for scooters is so great, that drivers shouldn't even calculate. If your gas mileage is significantly more than what is listed above, you may have either calculated something incorrectly or there is something wrong with your vehicle.

Author Jason Lancaster, an auto industry veteran, developed AccurateAutoAdvice.com. You'll find accurate advice on gas mileage advice and how to figure out gas mileage.