Mileage expenses fall under the category of miscellaneous itemized deductions on your taxes. Per IRS rules, you can only claim the amount of expenses that is more than 2 percent of your adjusted gross income.So if you earn $40,000 a year, you could deduct any mileage expenses of more than $800 annually.To help calculate your deduction, read the 2014 mileage rate schedule.he company said I can deduct the mileage on my taxes since they don't reimburse me for it. For my old job, I drove to the construction office and then took a work car to the job site, so this is very different from what I'm used to.