Per diems are policy guidelines for reimbursing different types of travel expenses.

These guidelines typically vary by location and time of the year. Per diem guidelines break down these expenses into the following components:

• Lodging - Includes expenses for overnight sleeping facilities, baths, personal use of the room during daytime, telephone access fee, and service charges for fans, air conditioners, heaters, and fires furnished in the room when such charges are not included in the room rate. (For CONUS, lodging taxes are excluded.)
• Meals - Expenses for breakfast, lunch, dinner and related tips and taxes. (Specifically excluded are alcoholic beverage and entertainment expenses, and any expenses incurred for other persons).
• Incidental - Miscellaneous fees such as the following:
  • Fees and tips given to porters, baggage carriers, bellhops, hotel maids, stewards, stewardesses, and so on
  • Transportation fees between lodging, places where meals are taken, and place of business
  • Mailing costs associated with filing expense reports and mailing payments to personal credit cards