It’s no secret that it costs money to drive a car. Even if your car is paid for in full, you still have to pay for gas, insurance, registration, maintenance, and repairs. Cars are handy and helpful, but unfortunately, they’re not cheap.

For many car owners, it’s important to learn just how much it costs to drive. Of course, this is an imperfect science, as it’s impossible to predict when you’ll need repairs, and how much they will cost. Still, you can do a pretty good job calculating how much it costs to drive your car, and the process is pretty easy.

In this article, Part 1 explains how to calculate how much you spend on gas, Part 2 tells you how to figure out how much you spend per mile, and Part 3 shows how to determine maintenance costs.

### Part 1 of 3: How to calculate how much you spend on gas

You can’t get a perfect estimation of how much gas costs, since the prices are always changing. But you can get a very close approximation.

**Step 1: Fill your gas tank**. To get the most accurate calculation of your cost of driving, fill your gas tank completely, until the gas pump clicks off.

**Step 2: Reset your trip odometer**.

**Step 3: Drive until you have a quarter tank left**. Drive your car, without refilling it, until you have only a quarter tank left.

**Step 4: Refill your tank**. Refill your tank, but write down exactly how many gallons it takes to fill up.

**Step 5: Record the miles on the odometer**. Write down how many miles are on your trip odometer, and reset it.

**Step 6: Repeat this process**. Do this process two or three times to help ensure accuracy.

Then, divide the number of miles you drove by the amount of gas you purchased. This will give you an exact reading of how many miles per gallon your car is getting (you can also use your vehicle’s average mileage reading, if it has one, though it will be less accurate).

**Step 7: Average the prices**. From there, you have to figure out about how much gas costs, which you can do by averaging the prices from your trips to the station.

Divide the price by the number of miles to the gallon that your vehicle gets, and you have the cost that you spend on gas for every mile that you drive.

### Part 2 of 3: How to figure out how much you spend per mile

Of course, gas is not the only cost associated with your vehicle. You also have to spend money on registration and insurance. Calculating those costs are easy: check your bill, and see how much you’re spending. You can divide those numbers by 12 to determine your monthly prices, but you can also figure out how much you’re spending per mile you drive.

**Step 1: Track how many miles you drive for three months**. Then multiply the number of miles over that period by four (to get a year’s amount of miles).

**Step 2: Divide the amount you pay annually in registration and insurance by this number**. Then add it to your gas costs by mile. The result is a close approximation to how much you spend per mile on gas, insurance, and registration.

### Part 3 of 3: How to determine maintenance costs

There are some other car expenses you can add to your cost of driving, to get a more accurate representation of how much you spend. For instance, if you drive about 10,000 miles a year, you can account for three oil changes, a tire rotation, and a 10,000 mile inspection.

You won’t be able to accurately account for unforeseeable expenses such as leaks, damaged parts, and accidents, but you can at least incorporate some basic routine maintenance costs into your equation.

Knowing how much it costs to drive can be really helpful. It not only gives you a good idea of exactly how much you spend on your car, but it can also help you determine whether owning a vehicle is economically smart, or whether you should think about using rideshares and public transportation instead of owning a car.