Incidental expenses refer to small fees and tips that aren't part of meals, lodging, or flight expenses. Examples of incidental expenses include tips for hotel housekeepers, tips for bellhops at the hotel, and tips for baggage handlers at the airport.

An allowance for incidentals is a per-diem payment intended to cover the minor, often un-receipted costs associated with business travel. This typically includes things like tips for hotel staff (porters, housekeeping), small laundry expenses, telephone calls home, or local transportation for personal needs. For government and corporate travelers, this is usually a flat daily rate that does not require the submission of receipts, unlike major meals or lodging. In 2026, many government agencies (such as the Canadian government or the US State Department) set specific incidental rates based on the location's cost of living; for instance, the incidental rate might be 20% to 32% of the total daily meal allowance. When staying at a hotel, you will often see an "incidental hold" on your credit card at check-in (usually $50–$100 per night); this is different from a "per-diem allowance." The hotel hold is a temporary block to cover potential room charges like the minibar or movie rentals. In contrast, the travel allowance is money paid to the traveler to ensure they aren't out-of-pocket for the small but necessary costs of living on the road for work.