# Can poor gas mileage justify a new car purchase?

I feel like my whip is dying. My sled. My wheels. Fine, my soccer mom car. It has over 160,000 on it. I don’t really want to buy a new (to me) car, but my current car isn’t acting completely right. Yesterday when I was driving, I started trying to think of reasons why this might be a good thing. You know, because I’m in denial. My dinosaur brain ran across an idea to justify my future purchase via the gas mileage trade-off. Is this a real reason to make a car change? Or is it something that desperate, stupid people like me grasp onto in order to feel better?

Let’s use mathematics!

There are a few factors in this equation. The price of gas certainly matters. My current gas mileage is worth knowing, as is the prospective new car’s gas mileage. That’s about it. Oh, and some hypothetical average annual mileage.

Let’s start this conversation at \$3.25/gallon

My current car gets about 21 mpg on the highway. That means it costs me \$3.25 to go 21 miles. Or, 15.47 cents per mile. If I were to increase my gas mileage to 31 mpg, then it would cost me 10.48 cents per mile. If I drive 20,000 miles per year, then I’ve saved \$998 (\$83.16/month) in fuel costs, by switching to a car that gets 31 mpg.

Same math, different numbers. My current 21 mpg car costs me 17.86 cents per mile, at \$3.75/gallon. If I switch to a shiny new that gets 31 mpg, then it will cost me 12.09 cents per gallon. Switching cars when gas is \$3.75 would save me \$1,154 in fuel costs, if I were to drive 20,000 per year.