What is expense approval?
Expense approval is the sign-off between an employee submitting expenses and getting paid back. This cheat sheet covers how to think about it and what gets reports rejected. The detail is further down.
How to think about it
- It reviews money already spent. Expense approval happens after the trip. Pre-trip approval happens before a booking completes, while there's still time to change it.
- The chain has an order. A common sequence is the field supervisor first, the project manager next and finance last.
- Set dollar levels. An approval matrix shows who can approve what amounts. Larger companies often add a second approval level above $1,500 to $5,000.
- Routine items can pass. Lodging within budget limits can be approved automatically, so approvers spend their time on exceptions.
What gets reports rejected
- Hotel above the cap. A nightly hotel price over the policy cap.
- Meals over the limit. A meal total above the per diem limit.
- Missing receipts. No receipt for an expense over $75.
- No certification. Every report needs a line where the employee attests the expenses are legitimate and within policy.
Expense approval vs. pre-trip approval on Engine
| Expense approval | Engine pre-trip approval | |
|---|---|---|
| When | After the trip, when the report is submitted | Before the booking completes |
| What the approver sees | Line items by date and category, receipts and the business purpose | The current price, the booking details and the traveler's reason |
| Outcome | Approved for reimbursement or rejected | Approved and booked, or declined with a reason |
How it works on Engine
With Engine Approvals, all company admins are approvers by default, or admins can pick specific admins and add department managers. Requests expire after 24 hours, or at the end of the reservation day for same-day bookings, and the traveler hears the decision by email. For stays on Direct Bill, Engine pays eligible hotels and invoices the company, so the traveler doesn't front the room charge or claim it back.
Questions
Who approves expense reports?
Usually the employee's manager, with finance as a second approver at larger companies or above a dollar threshold. In project-based teams, a field supervisor may approve first, then the project manager, then finance.
How long do employees have to submit expenses?
Most companies require reports within 14 to 30 days of the trip. Under an IRS accountable plan, accounting for expenses within 60 days after they were paid or incurred is treated as a reasonable period.
What happens if a receipt is missing?
The traveler submits a card statement or bank record showing the charge, with a short note explaining the missing receipt. The manager can then approve or reject based on the context.
What if an employee was advanced more than they spent?
Under an accountable plan, the employee returns the excess. Returning it within 120 days after the expense is treated as a reasonable period, and amounts not returned are treated as paid under a nonaccountable plan.
Sources
- Engine, Expense Approval Process: A Step-by-Step Guide For Crew-Based Travel, accessed November 2, 2026.
- 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.
- Engine, Approval Workflows for Out-of-Policy Bookings, accessed November 2, 2026.
- Engine, Company Travel Policy Enforcement, accessed November 2, 2026.
- Engine, Direct Bill for Company Hotel Travel, accessed November 2, 2026.