Quote Originally Posted by WhereRWe? View Post
How you pay for gas makes a difference, too. We use a credit card that pays us 5% back on all purchases at gas stations, drug stores and supermarkets. As long as you pay the balance on your credit card each month, that can add up to REAL savings.
True. And One thing I point out to people is as the price of gas gets higher - generally the percentage of difference between regular and mid-grade and super gets smaller and smaller, making it more of a possibility that using a higher grade of gasoline might be more economical. For example, If you are currently running regular gas in a vehicle that gets 22 MPG, and lets say the price of gas is $3.40 reg; $3.50 mid; $3.60 super. You would only have to get 22.7 MPG on mid grade to make it worth your money, or 23.3 MPG on super. Not all vehicles will show an improvement in mileage with different grades of gasoline, but many do. We have an '93 Dodge Dakota which does not seem to benefit from the different grades. We also have an '04 Ford Escape that gets 2 MPG more on mid-grade than regular, making it well worth the extra price. Super does not make as big a difference in this vehicle. Something to consider, nonetheless.

If you want to calculate how many MPG you would have to get to benefit this is the simple formula:

Current MPG X Price of gas for the better grade / Price of your current grade

So for a current MPG of 18 MPG on regular gas at $3.45 a gallon compared to mid-grade at $3.55 a gallon:

18 X 3.55 / 3.45 = 18.5

So, for this example, you would only have to gain .5 MPG to make the mid-grade pay for itself.