Updated September 2026
Fuel is the number you notice, not the number that matters
Fuel is the only cost you pay in public, standing next to a display that counts up. Everything else arrives as an annual premium, an unexpected repair, or a resale value you never see as a transaction. So fuel feels like the cost of driving, and for an ordinary car it is closer to a quarter of it.
That matters the moment you are quoting a delivery, billing a client for travel, choosing between two cars, or deciding whether a job forty miles away is worth taking.
What belongs in the total
| Cost | Include it? | Where to find it |
|---|---|---|
| Fuel | Always | Your fill-up log, or bank statement search for the stations |
| Maintenance and repairs | Always | Service invoices for the year |
| Tyres | Always | Set price divided by the years you expect them to last |
| Insurance | Always | Annual premium |
| Registration, tax, inspection | Always | Annual paperwork |
| Depreciation | Business: yes | Value at the start of the year minus value at the end |
| Loan or lease payments | Instead of depreciation | Twelve monthly payments |
| Parking and tolls | Only if routine | Monthly parking, regular commute tolls |
Do not count depreciation and loan payments. They are two ways of measuring the same thing, and adding both roughly doubles the largest line in the calculation.
A worked example
A paid-off 2019 sedan, 12,000 miles in the year, averaging 29 MPG.
| Line | Year | Per mile |
|---|---|---|
| Fuel (414 gal at $3.29) | $1,362 | $0.114 |
| Maintenance and repairs | $700 | $0.058 |
| Tyres | $220 | $0.018 |
| Insurance | $1,400 | $0.117 |
| Registration and inspection | $180 | $0.015 |
| Depreciation | $1,900 | $0.158 |
| Total | $5,762 | $0.480 |
Fuel is 24 percent of that total. Insurance costs slightly more than the fuel does, and depreciation costs more than both. Anyone budgeting on fuel alone is out by a factor of four.
Put a new car with a $480 monthly payment in place of the depreciation line and the same 12,000 miles land near 80 cents a mile. The driving did not change. The vehicle did.
Standard rate against actual expenses
If you deduct vehicle costs for work in the US, you pick one of two methods and you should pick the one that gives you more money.
- Standard mileage rate. A flat rate per business mile. You keep a mileage log and nothing else. Easy, and usually better for an efficient, cheap-to-run car with high annual mileage.
- Actual expenses. The real costs, times the share of miles that were business. More paperwork, and usually better for an expensive vehicle, a heavy depreciation year, or low annual mileage.
The calculator above shows both sides of that decision. Verify the current year's rate on irs.gov before you file, because it changes most Januarys, and note that switching methods after the first year has rules attached. This is a calculator, not tax advice.