What is an expense report?
An expense report is how an employee asks to be paid back for business spending. This cheat sheet covers how to think about one, the math behind the amount due, how to fill one out and why reports get sent back. The detail is further down.
How to think about it
- It's a reimbursement request. It itemizes what was spent, when and in which category, and totals what the company owes the traveler.
- Receipts carry it. Under IRS rules, lodging needs a receipt at any amount, and most other expenses need one at $75 or more.
- Someone signs off. A supervisor usually has to approve the report before the expenses are reimbursed.
- Timing affects taxes. Under an accountable plan, the IRS treats accounting for expenses within 60 days and returning any excess within 120 days as on time.
The math
Net amount due = total claimed, minus any cash advance, minus anything already paid on a company card.
A traveler claims a $438 hotel, $312 airfare, $87 in rideshares and $204 in meals, for $1,041. The airfare went on a company card, so $1,041 - $312.
$729
Illustrative example built on the sample in Engine's business travel expense report template.
How to fill one out
- Collect receipts during the tripSave hotel folios and confirmation emails as they arrive, and photograph meal receipts right away.
- Categorize each expenseMap every line to a category such as lodging, airfare, ground transport, meals, mileage or other.
- Check it against your policyCompare each line with the nightly hotel cap, the meal per diem and the receipt rules before you submit.
- Total itAdd the category totals, then subtract any cash advance or company card charges to get the net amount due.
- Submit on timeSend it as soon as you return. Late reports routinely trigger hold-ups or partial denials.
Why reports get sent back
- Hotel over the nightly cap. One of the most common reasons a report is rejected or delayed.
- Meals over the per diem. Easy to catch before submission, much harder to fix after.
- Missing receipts. If a receipt is lost, send a card statement or bank record showing the charge with a short note.
- Personal costs mixed in. Mixing personal and business charges on one report gives finance a reason to send the whole report back.
What goes on an expense report
| Category | Typical line items | Usually not reimbursable |
|---|---|---|
| Lodging | Room, taxes, required fees | Mini-bar, in-room movies, personal spa services |
| Airfare | Base fare, plus seats or bags if policy permits | First-class upgrades, personal leisure flights |
| Ground transport | Rideshare, taxi, rental car, tolls | Traffic or parking fines |
| Meals | Business meals, solo meals up to the per diem, tips | Alcohol beyond approved client entertainment |
| Mileage | Personal car used for work, at the IRS standard rate | Your normal commute to the office |
How it works on Engine
When a hotel is booked on Engine, the folio is delivered to the reservation after checkout, so travelers don't have to request it. Engine reporting uses booking and billing data plus company fields like department, project and cost center, so finance can filter travel spend without assembling scattered records. Trips booked outside Engine aren't included automatically.
Questions
What should an expense report include?
The employee's name, department, manager, trip dates, destination and business purpose, plus a project code or cost center if finance allocates costs that way. Each line needs a date, vendor, category and amount, plus a receipt for any cost over the company's receipt threshold.
What if a receipt is missing?
Submit a card statement or bank record showing the charge, with a brief note explaining the missing document. The manager can then approve or reject the line based on context.
How soon should I submit an expense report?
Most companies require reports within 14 to 30 days of finishing the trip. For tax purposes, the IRS treats accounting for an expense within 60 days as a reasonable period under an accountable plan.
Are expense report reimbursements taxable?
Not if the company reimburses under an accountable plan, which requires a business connection, adequate accounting and the return of any excess. Reimbursements under a nonaccountable plan are reported as pay.
Sources
- Engine, Business Travel Expense Report Template (Free), accessed November 2, 2026.
- Engine, Travel Expense Reporting: A Complete Guide, accessed November 2, 2026.
- Internal Revenue Service, Publication 463 (2025), Travel, Gift, and Car Expenses, accessed November 2, 2026.
- Association of Certified Fraud Examiners, Fraud Risk Exposures and Descriptions, accessed November 2, 2026.
- Engine, Travel Reporting and Analytics, accessed November 2, 2026.
- Engine, Direct Bill for Company Hotel Travel, accessed November 2, 2026.