You cannot enter a per diem expense type twice for one day. Additionally, you cannot enter a per diem expense item and an expense item covered by the per diem for the same day. For example, if the per diem expense type covers breakfast, you will receive a warning if you enter a per diem expense item and a breakfast expense item for the same day.

A per diem expense is a fixed amount that covers all expenses in a day. Typically, per diem expenses exclude primary transportation (such as airfare or rail fare) and hotel expenses. Meal expenses for an individual are typically included in the per diem, but meal expenses that include business guests can be expensed separately (if allowed by the per diem rules).

Tax-free per diem rates (the amount of the per diem limit that is not taxable income) and rules for claiming per diem reimbursement are established by each country. Companies can set per diem rates that are above or below the tax-free rate. Amounts submitted for reimbursement over the tax-free per diem amount (if allowed by the company's rules) are considered taxable income.

Per diem limits are prorated for the length of business travel based on established intervals (for example, 6 - 14 hours, 14 - 24 hours).

For per diem reimbursement, receipts are not required, and you cannot claim Value Added Tax (VAT) reimbursement.

A per diem expense item cannot be itemized. Also, when itemizing an expense item, you cannot add a per diem expense item to that expense item.