If you use the standard mileage method, that includes allowances for all car expenses; gas, maintenance, tires, oil changes, depreciation and insurance. The only thing you can add on top of the standard method is parking fees and tolls.
To use the standard mileage method method you must have an accurate log of your business miles (date, purpose of trip, # of miles).
If you use the actual expense method, you add up all your car expenses for the year; gas, maintenance, repairs, insurance, depreciation. You can't include car loan payments but you can include lease payments if you lease. You also add up all your miles driven; personal and business, and get the percent that you used the car for business, and deduct that percent of expenses. You need the same accurate log of your business miles plus you need the start and end odometer for the year to get your total miles and personal miles.
The standard method is more lucrative for most people and less paperwork.
