Travel Expense Reimbursement: A Complete Guide

Every business trip generates a small pile of costs beyond the ticket and the hotel booking — taxis, tips, a forgotten charger, a client lunch. Travel expense reimbursement is the system that sorts out which of those come back to you, and which quietly don't.

What travel expense reimbursement actually is

Travel expense reimbursement is how employers pay back employees for out-of-pocket costs incurred on business trips. To stay tax-free, reimbursements must follow IRS accountable plan rules — see our full accountable plan guide for the exact three-part test that governs this.

What expenses can be reimbursed

• Lodging: hotel stays or short-term rentals for business travel. Often reimbursed at the actual cost up to the GSA lodging cap for that destination.
• Meals & incidentals: covered via a flat per diem or actual receipts. The GSA M&IE rate is the standard benchmark — see our full M&IE breakdown.
• Transportation: airfare, train, rental car, taxi, rideshare, and mileage if you drive your own vehicle, reimbursed at the IRS standard mileage rate.
• Parking and tolls: typically reimbursed at actual cost on top of per diem.
• Conference fees, business calls and essential supplies: can be included if the employer policy allows.

What is NOT reimbursable

• Personal meals when you are not away from home overnight.
• Commuting from home to your regular workplace.
• Alcohol, unless your policy explicitly covers client entertainment.
• Personal side trips added to a business journey.

How to submit a travel expense claim

• Complete an expense report with dates, destination and business purpose.
• Attach receipts for lodging and any out-of-pocket meals above the per diem limit.
• Attach a mileage log if you drove your own vehicle — see our mileage reimbursement calculator for a fast way to total multi-leg trips.
• Submit within the deadline set by your employer (typically 30-45 days after returning).

“Ordinary and necessary expenses paid or incurred while traveling away from home in pursuit of a trade or business may be deducted or reimbursed.”

— Internal Revenue Service, IRS Publication 463, irs.gov

Tax-free vs. taxable reimbursement

Reimbursements within the GSA per diem rates, supported by a trip report, are generally tax-free — see is per diem taxable? for the full breakdown. Amounts above the federal per diem, or any amount paid without documentation, become taxable wages. Our per diem calculator works out a GSA-rate total you can attach directly to your expense report, keeping the whole claim inside the tax-free range from the start.