Can you keep unused per diem? If your employer requires you to fill out a per diem expense report and reimburses your spending, then you won't have any leftover funds. But if your employer chooses to pay you a flat amount for per diem instead, then you're generally able to keep any money you don't use.

Yes, you can generally "pocket" any unused per diem money, provided your employer uses the fixed-rate (allowance) method rather than the "actual expense" reimbursement method. Under IRS rules in 2026, if your company gives you a flat daily rate (e.g., $75 for meals and incidentals) and you only spend $30, you are legally allowed to keep the remaining $45 tax-free. This is because the per diem is considered a "substantiated" expense that does not require individual receipts for meals, as long as the rate stays within the federal GSA limits. However, if your employer requires you to submit receipts and only pays for what you actually spent, you cannot keep the difference. It is also important to note that if your per diem exceeds the federal limit, the excess amount may be treated as taxable wages. For most business travelers, the "meal and incidental" (M&IE) portion is the easiest to save on, as choosing budget-friendly food options allows them to keep the surplus as an unofficial "bonus" for the inconvenience of travel.