Taxpayers
can use the optional standard mileage
rates to calculate the deductible costs of operating an automobile.
Standard mileage for business use of an automobile remains
at 55½ cents per mile, consistent with that rate in
place in the latter half of 2011. For medical or moving expenses,
the rate is 23 cents per mile, a half-cent decrease from
the second half of 2011. The standard mileage rate allowed
for services to charitable organizations is 14 cents per
mile.

Alternatively, rather than using the standard mileage rates,
taxpayers may instead use their actual costs if they maintain
adequate records and can substantiate their expenses. The
rules for substantiating these amounts appear in Rev. Proc.
2010-51.
For automobiles a taxpayer uses for business purposes, the
portion of the business standard mileage rate treated as
depreciation is 23 cents per mile for 2012, increased from
22 cents per mile allowed in 2011.