per diem reimbursement rules
A per diem allowance is a fixed amount of daily reimbursement your employer gives you for your lodging, meals, and incidental expenses when you are away from home on business. (The term incidental expenses is defined in chapter 1 under Standard Meal Allowance.he standard meal allowance is for a full 24-hour day of travel. If you travel for part of a day, such as on the days you depart and return, you must prorate the full-day M&IE rate. This rule also applies if your employer uses the regular federal per diem rate or the high-low rate.