For the final six months of 2008, the IRS is increasing the optional standard mileage rates for business by 8 cents per mile, from 50.5 to 58.5. The IRS normally updates mileage rates once a year in the fall for the next calendar year; this midyear adjustment is a special adjustment due to recent gasoline price increases. “Given the increase in prices, the IRS is adjusting the rates to better reflect the real cost of operating an automobile,” IRS commissioner Doug Shulman said in a press release.

Taxpayers can use the rates to calculate the deductible costs of operating a vehicle for a business. However, taxpayers always have the option of calculating the actual costs of using their vehicle rather than using the standard mileage rates.