Per Diem Calculator: GSA Lodging and M&IE with 75% Rule

Per diem: flat-rate travel money, done by the book

Per diem replaces receipt-chasing with flat daily rates: lodging per night plus M&IE (meals and incidentals) per day. A 4-day trip at the GSA standard ($110/$68) reimburses $330 lodging + $238 M&IE = $568 - with travel days automatically at 75% of M&IE, the detail every manual calculation gets wrong. Reimbursement at or below GSA rates stays tax-free to the employee and deductible to the company.

The rules that trip people up

A 4-day trip has 3 lodging nights. First and last days pay 75% of M&IE regardless of departure time. Lodging above the GSA cap requires either receipts-based reimbursement or the excess taxed as wages. Self-employed travelers can use M&IE per diem but must deduct actual lodging with receipts - the lodging per diem is employees-only.

Employer or employee - why per diem wins

No receipt archaeology, predictable trip budgets, no "is a minibar water incidental" arbitration. Employees keep what they don't spend; companies cap exposure. The only real decision is the rate table: GSA rates for defensibility, or company rates at/below them.

Day trips break the per diem model entirely

No overnight stay means no lodging night, and the IRS treats meal reimbursement as taxable wages unless the trip requires rest away from home overnight - the "sleep or rest" test. A round trip that leaves at 6am and returns at 9pm books zero lodging nights, so reimbursing it as tax-free per diem is wrong: it's a taxable meal allowance that belongs on a paycheck, not an expense report. This calculator's nights-equal-days-minus-one math already reflects that split; a 1-day entry returns 0 lodging nights by design, not a rounding artifact.

Deduct the meal that's actually provided, not a share of the day

When a conference or client covers one meal, GSA's M&IE isn't one number you can split into thirds. It's four line items - breakfast, lunch, dinner, incidentals - that sum to the daily total, each with its own published rate. Subtracting "1/3 of M&IE" for a provided lunch either overpays or underpays versus pulling the actual lunch line from the GSA meal breakdown table. Get it wrong at scale and the shortfall either shorts the traveler or creates a taxable-wage gap between what was reimbursed and what the accountable plan actually allows.

High-low method vs city-by-city lookup

Instead of pulling a per diem rate for every destination county, the IRS also permits its high-low substantiation method: one flat rate for designated high-cost localities, a second flat rate for everywhere else in CONUS, each split into its own lodging and M&IE pieces. It trades precision for consistency - useful when crews rotate through a mix of cities and nobody wants to look up a new county rate every week. The catch: once an employer applies high-low to a given employee, it has to stay high-low for that employee for the rest of the calendar year. Mixing methods mid-year for the same traveler isn't allowed, even if a later trip lands in a city with a published GSA rate that would pay out differently.

Weekend layovers still draw full per diem

A Saturday-night stay bought to cut airfare isn't a first or last travel day just because it falls outside the workweek - the 75% haircut only applies to the actual departure and return dates. A Monday-to-Friday-plus-Saturday trip pays 75% M&IE on Monday and Saturday (or Monday and the actual last day, if travel ends Sunday), full M&IE on Tuesday through Friday, and full lodging every night in between, weekend included. Skipping the extra hotel night to "save" the company money often costs more once you compare it against a same-day last-minute fare, which is the actual math worth running before cutting a trip short.

The 75% travel day math, done for every M&IE tier

The calculator trims first and last days to 75% for you, but expense reports get checked by hand, and 75% of $86 is not a number anyone does in their head. Here is every GSA FY2026 M&IE tier with the travel day value precomputed, so you can audit a claim in seconds.

Quick check for any trip: the middle days pay the full rate, the two ends pay the middle column.

Trucker per diem: $80 a day and an 80% deduction

The transportation industry gets its own flat rate. Under IRS Notice 2025-54, drivers and crews subject to DOT hours of service limits can use a special M&IE rate of $80 per day in the continental US, $86 outside it, instead of chasing city rates. Better, DOT workers deduct 80% of that meal cost, not the 50% everyone else gets.

Worked example: a self-employed OTR driver logs 280 full days away from home in a year. 280 x $80 = $22,400 of M&IE, and 80% of that is a $17,920 deduction. At a 22% marginal rate that is roughly $3,900 in federal tax saved. The 75% rule still trims the first and last day of each tour to $60, and W-2 company drivers are out of luck entirely: unreimbursed employee expenses stopped being deductible in 2018.

High-low method: the actual dollar figures

The FY2026 high-low rates under IRS Notice 2025-54 are $319 per day for listed high-cost localities and $225 per day everywhere else, unchanged from the year before. The M&IE portions are $86 and $74, and everything above the M&IE portion is the lodging allowance.

Worked 5 day trip to a high-cost city: lodging is $319 minus $86, so $233 x 4 nights = $932. M&IE is 3 full days x $86 = $258 plus two travel days at $64.50 = $129. Total: $1,319 for the trip, no city-by-city lookup needed.

Self-employed: the deduction is smaller than the per diem

Worked example: a consultant spends 12 nights at a client site. Hotel receipts total $1,680, deductible in full, since lodging per diem is off the table for the self-employed. Call it 12 full M&IE days at $68 = $816, cut to $408 by the Schedule C 50% meal limit. Total deduction: $2,088, versus roughly $2,136 an employer could have reimbursed tax free at standard rates.

If you bill those travel days, price them with the day rate to hourly calculator; if the gap is pushing you toward an entity change, run the S corp tax savings calculator, and stack the home office deduction on top for the weeks you are not traveling.

The 60 day clock that keeps per diem tax free

Per diem stays off the W-2 only inside an accountable plan, and the plan has deadlines. The IRS safe harbor: substantiate the trip (dates, place, business purpose) within 60 days of the expense, and return any excess advance within 120 days. Miss the window and the whole reimbursement flips to taxable wages: the employer owes roughly 7.65% payroll tax on it and the employee pays income tax on every dollar. On the $1,319 high-low trip above, a late expense report costs the employer about $101 and the employee about $290 at a 22% bracket.

Related tools

Field crews traveling to jobs? Roll per diem into quotes with the job costing calculator. Self-employed: the M&IE deduction flows into your 1099 tax estimate. Reimburse mileage too - it stacks with per diem.