Mileage Per Diem Rate 2025. * airplane nautical miles (nms) should be converted into statute miles (sms) or regular miles when submitting a voucher using the formula (1 nm equals 1.15077945 sms). The irs makes it easy for business travelers by.

The irs makes it easy for business travelers by. Learn how the irs sets the mileage rate, why it matters for tax.