What It Really Costs to Run Your Car: A Worksheet

Your fuel bill tells you what it costs to keep moving. Your bank statement shows when the bills arrive. Neither, on its own, tells you the full cost of owning the car.

Make two totals: money you need to pay during the next 12 months, and the cost of owning and using the car over that period. Keeping them separate makes a paid-off car, a financed purchase and a replacement candidate easier to understand.

Use this worksheet on paper or copy it into your own document. It does not calculate or save entries.

Start with the same year and mileage

Write the car's exact version, your planning dates and expected annual mileage. For an existing car, dated odometer readings provide a useful starting point; adjust for a changed commute or planned trips.

Car / version: ____________________

From / to: ____________________ Annual miles: __________

Give every entry a source and date: an insurance quote, utility tariff, service invoice or clearly labeled assumption. Use the same period and mileage when comparing cars.

The EPA label's annual electricity cost assumes 15,000 miles and a projected electricity price. Those are comparison assumptions. Replace them with your own inputs.

Calculate the energy you will buy

The DOE's cost methodology calculates fuel quantities before multiplying by unit prices. This keeps mileage, efficiency and price visible.

For gasoline, use consumption representative of your driving or start with the exact version's EPA rating. If calculating city and highway separately, calculate the gallons for each and add them; do not take a simple average of two mpg figures.

For an EV, check what the consumption number includes. EPA's testing explanation places its efficiency measurement at the wall and includes Level 2 AC charging losses. Its label-based consumption estimate therefore does not need another blanket charging-loss percentage. A dashboard's battery-use figure may have a different boundary: check the vehicle documentation before treating it as electricity purchased.

Separate home and public charging. A home's meter and a public charger's billing meter need not measure at the same point, and public DC charging differs from EPA's AC test basis. Prefer actual billed kWh and receipts as records accumulate. For an initial estimate, record the assumed energy share and price for each source; mark the result approximate. Add session, subscription or idle fees separately, and use the applicable home charging tariff, including relevant variable charges.

Hypothetical example: 12,000 miles at 30 mpg requires 400 US gallons. At an assumed $3.50 per gallon, that is $1,400 a year. Separately, an EV assumed to require 30 billed kWh per 100 miles uses 3,600 kWh. At an assumed $0.20 per kWh, that is $720 before other fees. These invented inputs illustrate arithmetic, not current prices or a vehicle comparison.

For a plug-in hybrid, account for both gasoline and electricity actually used. Do not apply each fuel calculation to all the miles. Charging time is another consideration; our charging-curve guide explains the difference between peak power and the session you experience.

Fill in the annual cash worksheet

Enter acquisition taxes and fees once, wherever they are paid; do not add them again if already included in the financed payments or cash purchase entry.

Insurance and registration are largely fixed within a given year's assumptions. Fuel varies with use; maintenance depends on time, mileage and condition. Use the correct maintenance schedule to identify upcoming work and obtain quotes for known needs.

A repair reserve is money set aside, not a prediction that repairs will cost that amount. Show it separately from payments. When a repair is paid from that reserve, count the repair once. Dividing annual payments by 12 helps budgeting, but keep due dates: an annual insurance bill does not arrive in twelve equal pieces.

Add the ownership view without counting twice

Argonne's ownership-cost research includes depreciation alongside financing and operating expenses. For an existing car, estimate depreciation as its value at the start of the period minus its expected value at the end. Record a range if resale value is uncertain.

Ownership cost = operating expenses + depreciation + loan interest and fees + other applicable costs counted once.

Exclude loan principal and the purchase/down payment from this second total: depreciation represents the vehicle value consumed during the period. The CFPB distinguishes principal from interest; your lender's statement can supply the split.

For a car bought at the start of this 12-month period, use its purchase price after discounts minus its expected value 12 months later. Do not subtract your trade-in allowance, down payment or loan amount from that purchase price: those describe how you fund the purchase. Keep taxes and acquisition fees consistent—inside the starting amount or added separately, never both. If comparing several years of ownership, extend every expense and the resale estimate to that same period. This simplified view excludes the opportunity cost of your cash.

Finally, change one uncertain input, such as mileage or resale value, and write down how much the result moves. That identifies which quote or missing record is worth obtaining next.