What is the mileage expense rate?

The mileage expense rate for 2015 is 57.5 cents per mile when driving for business, 23 cents when moving or driving for medical reasons, and 14 cents when driving for charity, according to the Internal Revenue Service. Most taxpayers can claim the standard mileage rate or their actual operating costs.

The mileage expense rate takes into account the complete cost of operating a vehicle, including insurance, repairs and the fluctuating price of gas, the IRS notes. Taxpayers can't use the standard mileage deduction if they have taken an accelerated depreciation for their vehicle, including deductions taken as Section 179 expenses.