Online Gas Price Sites - Do They Really Save You Money?

June 29th, 2008 | by Brian Carr |

With the national average price of gasoline holding steady above $4 per gallon, it seems as if more and more people are using online gas price sites like Gasbuddy.com and GasPriceWatch.com to help determine where they’re going to go to fill up. While there’s certainly plenty of satisfaction in knowing you’ve picked up the cheapest gas in the area, is it possible that these sites are actually causing you to spend more on gas even if you’re paying less at the pump?

Confused? Let me give you the following example:

You drive a car that gets, on average, 20 miles per gallon and has a 10 gallon tank. Before leaving your house to fill up the car, you check out GasBuddy.com and see that the gas station closest to your house, which is only a mile away, is selling regular unleaded gas for $4.15 per gallon; however, another station that’s only six miles from your house is selling regular unleaded gas for $4.00 per gallon.

Certainly, it would be a no brainer to go to the $4 per gallon station. After all, assuming you have to fill up all 10 gallons, you’re going to save yourself a whopping $1.50:

$4.15 - $4.00 = 15 cent savings per gallon x 10 gallons = $1.50 savings

Now, if this is where the analysis stopped, you’d probably be feeling pretty good about your decision to go to the farther away station. I mean, $1.50 doesn’t seem like much, but you’d much rather have it in your account than hand it over to the gas station clerk, right?

As I’m sure you’ve already guessed, this isn’t where the analysis stops, so let’s continue:

At 20 mpg, you’re burning 1/20th of a gallon of gas for every mile you drive.

1/20 x 2 miles (close station) = 1/10th of a gallon of gas used for the round trip.

1/20 x 12 miles (farther station) = 3/5ths of a gallon used for the round trip.

$4.15 x 1/10 = 41.5 cents in burned fuel to go to and from the closer/more expensive gas station.

$4.00 x 3/5 = $2.40 in burned fuel to go to and from the farther/less expensive gas station.

So, by going to the farther away gas station, here’s what your net savings actually ends up being:

$1.50 + $.415 - $2.40 = -$.485.

By driving out of your way to save 15 cents per gallon of gasoline, you actually end up being about 50 cents in the hole. Again, I know these numbers don’t seem like much, but wouldn’t you rather keep your money? Besides, over time, ever little bit adds up.

It’s probably unlikely that you’ll do this sort of analysis before you decide where to purchase your next tank of gas, however, it is something that you should probably keep in mind. Long story short, unless you’re going to save a significant amount on each gallon of gas, or you need to fill up a mammoth tank, its probably not worth it to go out of your way to purchase gas.