Math was never one of my favorite subjects in school, but one I thing I knew was you needed to have the right numbers to have any chance of getting the correct answer.

One favorite activity of Volt owners and critics alike is to break down the cost of driving the Volt by taking into account the cost to charge, the EV range of the car, the length of a round-trip daily commute and other factors. Recently, there have been some number circulating online about the cost to drive the Volt that are flat wrong – either the person doesn’t understand how the Volt works or they are paying roughly ten times the national average for electricity (in which case, they have other issues). But don’t worry – we're here to help set the record straight.

We’ll get into the math in a second, but first know that our owners have driven more than 25 million miles, with nearly 2/3 of those miles using no gas at all, and most customers traveling over 900 miles between fillups. We’ve seen stories from owners who, one year after taking delivery, are still using the same tank of gas that came with the car and others who have driven the Volt across the country. But the question remains – how much does it cost to drive the Volt? Get your calculators ready and I’ll share with you some numbers.

Next, you need to charge that battery. Yes, the Volt has a 16 kWh battery, but what you might not know is only 12.9 kWh is used for charging and driving – this is done to extend battery life. 9.6 kWh is used to propel the car and accessories and 3.3kWh is used in the charging process The average cost of electricity in the U.S. is $.12/kWh, so, take $.12 x 12.9 to get a cost to charge of $1.55, a far cry from the $18.56 to charge that I’ve seen some say online. Think about it – if it cost that much to charge, I really doubt we would have 93% of our owners say they are very satisfied with the car.

When that charge is depleted, whether you’re in the Lincoln Tunnel or on a highway, the vehicle switches over to extended-range mode, using a gas-powered motor/generator to keep you going another 344 miles by EPA estimates. When you are in extended-range mode, the EPA estimates you will get 35 city/ 40 highway mpg or 37 combined mpg. With a full tank and full charge, your total driving range is 379 miles.

Some might say “But Rob! You didn’t mention that you have to wait around for it to finish charging before you can take a trip!” Well, no, actually you don’t. If you forget to plug it in, you can still drive the car in extended-range mode until you either refuel (like people have been doing for years and years when they take road trips) or find a spot where you can recharge. You can drive across the country in the Volt in no more time than it takes to use a conventional car.

The other point to factor in is how far your commute will be and that will be different for everybody. What we know is that after 25 million customer miles, their average EV range is slightly more than the EPA estimate of 35 and this computes to an average cost per mile of $.03 - $.06. By comparison, a gas-powered vehicle that achieves a combined 30 mpg costs about $.13 per mile (based on gas prices averaging $3.90 per gallon).

Here’s one example. Let’s say your round-trip commute is 50 miles. In the Volt, you would spend $1.50 for 35 miles of EV range and then $.11143 per mile for the other 15 miles (assuming city driving and the $3.90 gas price mentioned above). $.11143 x 15 is $1.67. Add that to the $1.50 to charge and the cost for that 50-mile trip is $3.17.

Now, if you have a conventional car that gets 30 mpg, the cost for each mile is $.13. The cost for this 50-mile trip would be $6.50 ($.13 x 50). If your car gets 35 mpg, the cost per mile would be $.11143 and the cost for the trip would be $5.57.

So to summarize:

-Average cost to charge the Volt for 35 miles of EV driving: $1.50

-MPG of the Volt in extended-range mode: 35 city / 40 highway or 37 combined

-Average cost per mile so far from Volt drivers: $.03 - .06

-Cost per mile of a conventional vehicle that gets 30 mpg with gas at $3.90 per gallon: $.13

Math is hard, but when used for good, it can also be electrifying.

Note: This blog has been updated with information about the cost of charging the Volt.