For 2013 the standard mileage rates have been increased.
For business miles the deductible mileage rate is 56.5 cents per mile for business miles driven. For medical purposes the rate is 24 cents per mile and for charitable purposes it remains the same at 14 cents per mile.
This once cent per mile increase or about half a percent in business and medical mileage rates come after 2012 which was the year we saw the highest percentage increase in gasoline prices in history. Over the past 4 years gas prices have increased more than 100% while the mileage rate has decreased 2% from the 58.5 cents at the end of 2008.
For those who pay per diem rates or receive per diem rates for reimbursement of expenses while traveling rather than have an accountable plan for those reimbursements, the standard rate for lodging is $77 and for meals and incidental expenses is $46. As a typical practice most businesses I am familiar with pay lodging expenses directly and pay the per diem for meals and incidental expenses. The $46 is the standard rate and is often used as a company standard, but most locations have a rate specific to that location which you can use when traveling to those specific locations. You can find rates by location at:
http://www.gsa.gov/portal/category/21287
For travel OCONUS (Outside the Continental US) the rates are set by the State Department and you can find those rates at:
http://aoprals.state.gov/web920/per_diem.asp