How to Deduct Mileage Expenses for a Second Job

Typically, the Internal Revenue Service does not allow you to write off expenses incurred traveling to and from your job. If you work multiple jobs, however, you can include the mileage driven from your main job to your second job as a miscellaneous deduction on your income taxes. As a miscellaneous deduction, you can only claim the portion of the deduction exceeding 2 percent of your adjusted gross income, and you have to itemize your tax deductions to claim it.

Keep a mileage log documenting trips from your main job to your second job. Include the dates you drive, the distance you drove and why you made the trip. Only trips between your main job and your second job can be included.

Complete Form 2106 to document your deduction for the IRS. This form also allows you to claim any additional unreimbursed job expenses. Multiply your total mileage driven between your main job and your second job by the annual mileage rate for business. As of 2011, the rate equals 51 cents per mile. If you drove 1,200 miles in 2011, your deduction equals $612.

Report the amount of your deduction on line 21 of Schedule A as an unreimbursed employee expense. Combine this amount with any other miscellaneous deductions and report the total on line 24.

Report your adjusted gross income from line 38 of your Form 1040 tax return on line 25 of your Schedule A. Multiply this amount by 0.02 and report the result on line 26.

Subtract 2 percent of your adjusted gross income, the amount on line 26, from your total miscellaneous deductions, including your mileage expenses for driving to your second job, to find the deduction value for your miscellaneous expenses. This amount, plus your other itemized deductions, will lower your taxable income for the year.