We are assaulted by advertisements all the time.  Every time we turn on the TV or the radio we see and hear commercials.  Most of the commercials go in one ear and out the other, but every once in a while, something about an ad will make me stop and listen and then I start to think which is usually not good.

Today, I heard a commercial for a certain brand of gasoline with a great new additive that will help to prolong the life of my car.  Sounds nice.  Plus, there is almost always a “plus,” as an added bonus it will improve my gas mileage.  Well, who does not want better gas mileage?  But, being the kind of person I am, I had to ask, “How much of a difference will it really make?”

The advertisement states that using this product will restore an “average of 3 – 5 miles per tank.”  Notice that is per TANK, not per gallon.  So, they are losing my interest rather quickly, but just for fun (I know, I need to get out more!) let’s put some numbers to this and see what impact using this product would really have.

First, we need some numbers. So, let’s assume the following: 1) I buy a new car and will keep it for 15 years; 2) I will be an average US driver and drive 13,500 miles per year; 3) I will average 25.5 miles per gallon; 4) My gas tank holds 15 gallons of fuel; 4) the price of gas is $2.50.

Next, if we do the math, we will divide the miles driven (13,500 x 15) by the average MPG of 25.5.  The result is that I can expect to use 7,942 gallons of gas over the next 15 years.  So, if my gas tank holds 15 gallons, then I will use approximately 530 tanks over than time.  The ad claims an improvement of 3-5 miles per tank, so let’s go right in the middle and use 4 miles per tank.

OK, so 4 miles per tank means I will improve 2,120 miles over the life of the vehicle.  So, if the average MPG is 25.5, then that will save me 86.5 gallons.  If we assume the price of gas is $2.50, then I will save $216.25.  Well a dollar is a dollar, so $200 is nice.  But remember, that is over 15 years, so my average savings per year is a little less than $14,50, or not quite three Pepperoni Hot ‘N Ready’s.  

Now, I am not all that excited about what this product will do for me.  This is a major name brand of gasoline and often the major brands cost a little more.  So, if the price of this particular brand, on average, is more than $0.03 higher than the competition, the savings completely disappear. 

I am all for better gas mileage and I am all for saving money; however, it will take more than three pepperoni pizzas a year to get me excited about going out of my way for this brand of gasoline.