Can You Keep Unused Per Diem? Meals, Lodging, and Tax Rules

Whether you can keep unused per diem comes down to two things: how your employer’s reimbursement plan is structured, and which piece of the per diem you’re talking about. For meals and incidentals, most employers using the federal rate let you pocket whatever you don’t spend, tax-free, as long as the daily amount stays at or below the government figure. For lodging, you generally cannot keep the difference at all, because lodging reimbursement is limited to what you actually paid. The standard federal meal allowance for 2026 is $68 per day in most locations, and the standard lodging cap is $110 per night, with both figures running higher in expensive cities.

What Actually Controls the Answer: Your Employer’s Plan Type

The IRS splits employer travel reimbursement into two categories, and that split decides whether unused per diem is yours tax-free, yours but taxable, or something you have to return.

An accountable plan has three requirements: the expenses must be business-related, you must document them to your employer within a reasonable time, and you must return any excess reimbursement within a reasonable time. When those conditions are met, the payments never show up as wages on your W-2.¹ If you don’t return excess money that the plan requires you to return, the unreturned portion gets reclassified as taxable wages.

A nonaccountable plan skips one or more of those requirements. The most common version is a flat daily payment with no receipts required and no obligation to give anything back. You keep everything, but the whole payment becomes taxable compensation reported in Box 1 of your W-2.¹ Your employer also owes payroll taxes on the full amount.²

So the first thing to check is which plan you’re on. If your company requires expense reports and receipts and asks for money back when you’re overpaid, you’re on an accountable plan and the meals-and-incidentals surplus rules below apply. If they hand you a flat daily amount and never ask questions, everything they gave you is already taxable, and “keeping” it just means keeping post-tax money.

The Substantiation Deadlines

“Reasonable time” isn’t as vague as it sounds. The IRS safe harbor treats expenses as timely substantiated if you submit your report within 60 days of incurring the cost,³ and excess funds must be returned within 120 days of when the expense was paid or incurred.¹ Miss either window and your employer is supposed to treat the unreturned amount as taxable wages. Many companies set tighter internal deadlines, so read your own travel policy rather than assuming you have the full IRS window.

Keeping the Meal Surplus

The meals and incidental expenses (M&IE) portion is where the “keep what you don’t spend” question has a clean answer. When your employer pays the federal M&IE rate or less, you receive a flat daily allowance for food, tips, and small costs, and you don’t have to produce receipts for every meal. Spend $40 in a city where the federal rate is $68 and the remaining $28 is yours, tax-free.¹

The standard 2026 M&IE rate is $68 per day in most locations, scaling up to $92 in higher-cost areas.⁴ Employers that use the IRS high-low method instead of city-by-city rates treat $86 as the M&IE portion in high-cost localities and $74 elsewhere for the period beginning October 1, 2025.⁵ The keepability rule is the same either way: anything you don’t spend, up to the applicable M&IE rate, is yours.

Travel Days Pay Less

Your meal allowance is reduced on the days you leave and the day you return. For trips of 24 hours or more, you receive 75 percent of the applicable M&IE rate on the first and last days.⁶ At the standard $68 rate, that’s $51 on those days instead of the full amount. The same 75 percent rule applies to trips longer than 12 hours but shorter than 24 hours. Full days between departure and return pay 100 percent.

Provided Meals Shrink Your Allowance

If your employer or a conference provides a meal, your M&IE rate for that day drops by the value of each meal provided. At the $68 tier, the deductions are $16 for breakfast, $19 for lunch, and $28 for dinner.⁷ A conference that includes lunch and dinner cuts your $68 allowance down to $21 for that day. Multi-day events with catered meals catch travelers off guard, because the keepable surplus shrinks with each provided plate.

Same-Day Trips Don’t Qualify

Per diem is built for overnight travel. The IRS considers you traveling away from home only if your duties keep you gone long enough to require sleep or substantial rest, and a nap in your car doesn’t count.¹ If your employer pays a per diem for a same-day trip, that payment doesn’t qualify for tax-free treatment. The full amount becomes taxable wages regardless of what the company calls it.

Lodging: There Is No Surplus to Keep

Lodging works differently, and this is the boundary most people miss. The IRS is explicit that there is no optional standard lodging amount comparable to the standard meal allowance, and your allowable lodging expense is your actual cost.¹ The 2026 federal lodging cap is $110 per night in most locations,⁴ but the cap is a ceiling on reimbursement, not a flat amount you’re entitled to.

Federal rules require lodging receipts regardless of the dollar amount, and reimbursement is limited to the actual necessary cost of the stay. If the federal cap for your destination is $200 and you find a hotel for $150, the $50 difference goes back to the employer. Staying with a friend and pocketing the lodging rate isn’t an option under an accountable plan. Short-term rentals and home-sharing arrangements are treated as nonconventional lodging and are reimbursable at actual cost with a receipt, same as a hotel.⁸

When Keeping Per Diem Creates a Tax Bill

Three situations turn per diem, or the surplus you kept, into taxable income.

First, payments above the federal rate. Under Revenue Procedure 2019-48, the portion of any per diem allowance that exceeds the substantiated amount is treated as wages.⁹ Your employer must report the excess in Box 1 of your W-2 and withhold income and payroll tax on it,² with the non-taxable portion going in Box 12 under code L. Payroll taxes alone (Social Security at 6.2 percent plus Medicare at 1.45 percent on the employee side) run about $38 on a $500 excess before income tax enters the picture.

Second, patterns of abuse. If an employer routinely pays above the federal rate without requiring substantiation or treating the excess as wages, the IRS can reclassify the entire arrangement as a nonaccountable plan, making every dollar of per diem taxable rather than just the excess.⁹

Third, assignments that outgrow the “temporary” label. Per diem qualifies for tax-free treatment only when you’re on a temporary assignment away from your tax home, which the IRS defines as an assignment realistically expected to last one year or less. If an assignment is expected from the start to exceed a year, it’s indefinite, the location becomes your new tax home, and any per diem must be included in gross income even if every dollar is accounted for.¹ A six-month project extended to fourteen months can flip from temporary to indefinite, retroactively converting months of tax-free per diem into taxable wages. If there’s any chance your assignment stretches past a year, raise it with payroll early.

Records That Protect Your Keepable Surplus

Using the standard meal allowance frees you from collecting individual food receipts, but the IRS still requires documentation of the basic facts of every business trip: the cost of each lodging and transportation expense, the dates you left and returned, the city or area, and the business purpose. A contemporaneous log or calendar entry holds up in audit far better than reconstructed records. Lodging requires a receipt showing the hotel name, location, dates, and separate charges for the room and any other costs.¹

Keep these records for at least three years from the date you file the return that covers the travel.¹⁰ If income was underreported by more than 25 percent, the IRS has six years to audit, so six years is the safer horizon whenever there’s any ambiguity in how per diem was reported.

1
Internal Revenue Service. Publication 463 (2025), Travel, Gift, and Car Expenses
2
Internal Revenue Service. 2026 General Instructions for Forms W-2 and W-3
3
Internal Revenue Service. Rev. Rul. 2003-106
4
Federal Register. Maximum Per Diem Reimbursement Rates for the Continental United States (CONUS)
5
Internal Revenue Service. Special Per Diem Rates
6
eCFR. 41 CFR Part 301-11 Subpart A – General Rules
7
General Services Administration. M&IE Breakdowns
8
eCFR. 41 CFR Part 301-11 – Subsistence Expenses
9
Internal Revenue Service. Rev. Proc. 2019-48
10
Internal Revenue Service. How Long Should I Keep Records