The cost of driving a vehicle for business can be figured using actual expenses or an IRS-set mileage rate (there are some restrictions on this choice). The IRS-set mileage rate for 2018 is 54.5¢ per mile (up one penny per mile over the rate for 2017). The basis of the vehicle must be reduced by a deemed depreciation rate, which is 25¢ per mile, the same rate as in 2017. Be sure to note your odometer reading for the vehicle at the start of the year to help in reporting business mileage for 2018.