Per Diem: Employer Rules, Rates, and Tax Treatment

Per diem is one of the few pieces of payroll administration that makes life easier for everybody: the employee stops photographing receipts for sandwiches, and you stop checking whether a sandwich was reasonable. What it does not do is remove recordkeeping, and assuming it does causes almost every problem in this area.

This guide covers where the rates come from, the three conditions that keep the allowance out of taxable wages, the travel day rule almost everybody overpays, and whether any of it is required at all. The whole of the compliance question comes down to one distinction: the flat rate substitutes for proving how much was spent, never for proving the trip happened.

I build the people and records tooling for businesses without an HR department at FirstHR, and FirstHR is an onboarding and HR platform rather than a payroll provider. This is general information, not tax advice.

What Per Diem Is

Per diem is a fixed daily amount paid to an employee traveling away from home on business, in place of reimbursing what they actually spent. The published federal rates exist so that an employer paying at or below them does not have to prove the amount of the expense at all.

"Away from home" has a specific meaning, and it is not the same as away from the office. It means travel away from the general area of the employee's main place of work, for long enough to require sleep or rest. A long day trip to a client two hours away is business travel, but it is generally not a per diem situation.

The other useful distinction is between the two forms. A full per diem covers lodging plus meals and incidentals. A per diem for meals and incidentals only is common at small companies that book hotels directly, and it takes the largest and most variable cost out of the calculation entirely.

Is Per Diem Required by Law?

Not by federal law, and this is the question small employers most often ask first. No federal rule requires a private employer to pay per diem, to reimburse travel at all in most circumstances, or to use the federal rates if it does choose to pay something.

Two qualifications matter. First, several states require employers to reimburse employees for necessary business expenses, with California the best known of them (Labor Code section 2802), and in practice that covers travel costs incurred at the employer's direction. That makes the answer state-specific rather than a flat no. Second, federal contracting arrangements or collective bargaining agreements can impose their own requirements.

Where the Rates Come From

The General Services Administration sets per diem rates for the continental United States by locality, and they run on a federal fiscal year beginning October 1 rather than on the calendar year.

The standard rate covering locations without a specific listing is $181 per day effective October 1, 2026: $113 for lodging and $68 for meals and incidental expenses (General Services Administration). Hundreds of individual localities carry higher rates, and destinations outside the continental United States are set by other agencies entirely.

The locality element is the part small employers most often skip, usually by picking one company-wide number. That is understandable, but it costs money in both directions: overpaying against a low-rate destination creates taxable excess, and underpaying against an expensive one creates an employee who is subsidizing a work trip.

The Five Meals Tiers, and Looking Up a Destination

Lodging rates vary city by city, but the meals and incidental expenses component (M&IE on the federal rate tables) only ever takes one of five values. Learning that short ladder is faster than a lookup on most trips, and the published split behind each tier is what tells you what a single provided meal is worth (General Services Administration).

The first and last travel day column is the travel day rule already worked out for you, which is why this table is worth keeping near whoever fills in expense reports. Incidentals sit at $5 in every tier, so the whole difference in meals money between a cheap destination and an expensive one lives in the three meal columns.

For a specific destination, search the General Services Administration rate tool by city and state, or by ZIP code, choosing the fiscal year the travel falls in rather than the current one. A destination with no listing of its own takes the standard rate, and that is most of the map.

What Counts as an Incidental Expense

Incidental expenses are the small cash costs of being on the road: fees and tips given to porters, baggage carriers, hotel staff, and staff on ships. That is the whole federal definition, and it is narrower than most people assume, which is why the incidental share of the rate sits at $5 a day.

What the term does not cover matters more, because those costs get claimed as incidentals constantly. Laundry and dry cleaning, lodging taxes, telephone calls, transportation between the hotel and wherever a meal was eaten, and the cost of mailing an expense claim all sit outside it, per IRS Publication 463.

Several of those are reimbursable in their own right, lodging tax usually being one, but none of them come out of the incidental allowance. If you pay a meals and incidentals per diem, the practical read is that the incidental piece covers tips and nothing else.

The High-Low Method

The high-low method is a simplified alternative from the IRS that uses two rates in place of hundreds: a higher one for high-cost localities and a lower one for everywhere else (IRS Notice 2025-54). It exists because looking up localities is exactly the administrative burden per diem was meant to remove.

The IRS reissues these figures and the high-cost list every autumn, so a policy that names specific cities and amounts, instead of pointing to the current notice, will drift.

The high-low method also carries a consistency requirement. An employer using it for an employee must use it for that employee for the whole year, rather than switching to locality rates whenever they happen to be higher.

For a small business with occasional travel to a handful of cities, the high-low method is usually the right trade. For one whose people travel constantly to a single expensive location, the specific locality rate is likely to be higher and worth the lookup.

The Accountable Plan Rules

Whether a per diem is a tax-free reimbursement or additional wages turns entirely on whether it is paid under an accountable plan. Three conditions apply and they apply together (26 CFR 1.62-2).

The third condition is the one small businesses fail without realizing there was a condition. An advance paid for a five-day trip that ended after three days leaves two days of excess, and a policy that never asks for it back is not an accountable plan.

The consequence of getting this wrong is out of all proportion to the amount involved. A non-accountable plan does not just tax the excess; it makes every payment under the arrangement taxable wages, reportable on the W-2 and subject to withholding and payroll tax on both sides.

When It Becomes Taxable

A per diem turns from a tax-free allowance into reportable wages by five distinct routes, and they reach different amounts, from the excess alone to the whole arrangement.

The substantiation row is the one to notice, because that is where a false assumption bites. Employers hear that per diem means no receipts and conclude it means no paperwork, but no receipts is all it means.

A dated expense report naming the destination and the business reason takes two minutes, and it is the difference between a tax-free allowance and wages (IRS Publication 463).

Where an amount is taxable, it is treated as ordinary compensation, so it runs through payroll like any other wage item and appears on the W-2. That is a correction rather than a catastrophe, provided it is found in the same year.

Travel Days and Provided Meals

Under the federal method, two adjustments apply to almost every trip: a reduced meals rate on the first and last day, and a deduction for provided meals. Both are routinely missed, and each miss is a small overpayment that recurs on every journey.

The first is the travel day rule. Under the Federal Travel Regulation, the rulebook for federal employees' own travel, the meals and incidental portion is paid at 75 percent of the applicable rate on the first and last day of travel.

The logic of the travel day rule is obvious once stated: a flight arriving at 6pm does not involve a full day of meals. A three-day trip is therefore paid at 75 percent, 100 percent, and 75 percent rather than at three full days.

The IRS does not force that method on private employers. According to Revenue Procedure 2019-48 (section 6.04), an employer paying per diem may prorate by the Federal Travel Regulation method or by another method applied consistently and in line with reasonable business practice. Three quarters is the published figure, so it is the one to build in.

The second adjustment covers provided meals. Under the Federal Travel Regulation, a meal furnished to the traveler at no cost, such as a lunch inside a conference registration fee or a dinner the business paid for directly, comes out of that day's allowance at the amount published in the meals breakdown.

Hotel breakfasts are the exception people get wrong. Under the federal rule, a complimentary meal provided by a hotel or motel, and a meal served by a common carrier such as an airline, do not reduce the allowance (41 CFR 301-11.21).

The provided meal deduction is not a tax requirement for a private employer. Under Revenue Procedure 2019-48 (section 6.03), an employer need not reduce the rate for meals provided in kind, meaning supplied rather than paid for, as long as it reasonably believes the employee still incurred some meal and incidental expenses on each day of travel.

That makes the deduction a cost decision your policy settles once. Skip it, and a day when the conference supplied both lunch and dinner still pays the full meals rate, covering two meals the employee never bought.

Here is that calculation as a sheet. One row per day of the trip, with the travel day percentage and the provided meal deduction sitting in columns rather than in somebody's memory.

Setting a Policy

A per diem policy for a small business fits on a page. What matters is not its length but whether it answers these seven questions.

Settle where per diem sits among your other travel and expense rules at the same time. It belongs in the same document as the rest of your expense reimbursement policy, not in a separate note nobody can find.

Where Small Employers Get This Wrong

Small employers get per diem wrong in five predictable ways, and they differ in how far the damage reaches.

The last mistake is different in kind, because it breaks the third accountable plan condition. Under 26 CFR 1.62-2, an employee who keeps an excess the policy told them to return turns only that amount into wages. A policy that never requires the return, or a pattern of not enforcing it, makes the whole arrangement non-accountable, and that reaches every payment made under it.

Small businesses also have a version of this problem all their own. A flat monthly travel allowance paid to somebody regardless of whether they traveled is not a per diem at all: it is compensation, it is taxable, and calling it an allowance changes nothing about that.

A vehicle stipend paid as a flat amount works the same way, as wages rather than a reimbursement (IRS Publication 15).

Frequently Asked Questions