Per Diem Calculator
Updated August 2026 · Free · No sign-up
Calculate per diem for business travel — daily lodging and meal allowances under GSA rates, the first/last-day 75% rule, and when per diem stays tax-free versus becoming taxable wages.
Quick answer: Per diem = (full travel days × daily rate) + (first and last day × 75% of the M&IE rate). At the standard CONUS rate (~$178/day: $110 lodging + $68 M&IE), a 5-day trip pays 3 full days + 2 × 75% first/last days = $806 (lodging separate or included per policy).
How Per Diem Works
Per diem replaces receipt-by-receipt expense reports with flat daily allowances. The GSA sets federal rates that most US companies adopt: a standard CONUS rate for most locations plus higher city-specific rates for expensive metros (NYC, SF, Boston can run $300+/day combined). Two components:
- Lodging — per night, receipts usually still required at or under the cap.
- M&IE (meals & incidental expenses) — flat daily amount, no receipts.
The 75% rule: travel days (first and last) pay 75% of the M&IE rate, since part of those days is at home.
Worked Examples
Example 1 — standard 5-day trip. M&IE $68, lodging $110 × 4 nights. M&IE = 3 × $68 + 2 × $51 = $306; lodging = $440 → $746 total.
Example 2 — high-cost city. NYC-tier rates (~$80 M&IE): a 3-day trip pays $80 + 2 × $60 = $200 M&IE — always look up the city rate before defaulting to standard.
Example 3 — trucker M&IE. Transportation-industry workers use a special rate (~$80/day) and can deduct 80% of it — one of the few remaining unreimbursed-expense deductions.
Tax Treatment: The Rules That Matter
| Situation | Tax result |
|---|---|
| Per diem ≤ federal rate + expense report with time/place/purpose | Tax-free (accountable plan) |
| Per diem above the federal rate | Excess is taxable wages on your W-2 |
| No expense substantiation / no accountable plan | Entire per diem taxable |
| Assignment at one location exceeding 1 year | No longer "travel" — per diem becomes taxable |
That last row is the trap for long-term contractors: the one-year rule converts a tax-free stipend into wages the moment the assignment is expected to exceed 12 months.
Per Diem in Job Offers (Travel Nurses, Contractors, Consultants)
Travel-heavy roles often advertise "blended rates" — modest taxable wages + generous tax-free stipends. The evaluation math: a $25/hour taxable + $700/week tax-free package can out-net a $40/hour fully-taxed offer. But stipends have consequences: they don't count for 401(k) matches, Social Security credits, loan applications, or severance bases. And tax-free status requires maintaining a genuine tax home — duplicated living costs at a permanent residence. Compare full packages with the hourly to salary calculator on after-tax terms.
For Employers: Building a Clean Per Diem Policy
- Adopt GSA rates by reference (they update every October 1) — never hardcode dollar amounts in policy.
- Require the accountable-plan trio: business purpose, dates, location — expense apps make this trivial.
- Apply the 75% travel-day rule consistently; partial-day improvisation creates audit questions.
- Watch the one-year rule on long assignments and convert to taxable relocation treatment proactively.
- Mileage is separate: driving between cities pays the IRS mileage rate on top — see the mileage reimbursement calculator.
International Per Diem
The US State Department publishes foreign per diem rates by city (London and Tokyo exceed $400/day combined); the same accountable-plan logic applies. UK employers use HMRC benchmark scale rates instead; many EU countries publish statutory domestic per diems that double as tax-free ceilings.
Frequently Asked Questions
How is per diem calculated?
Full days × daily rate, with first and last travel days at 75% of the M&IE rate. Lodging is per night, usually receipt-backed under a cap.
What is the standard per diem rate?
The GSA standard CONUS rate — roughly $110 lodging + $68 M&IE per day, with hundreds of higher city-specific rates. Rates update every October 1; check gsa.gov for the current figures.
Is per diem taxable?
Not if paid at or below federal rates under an accountable plan (time, place, business purpose documented). Excess amounts and unsubstantiated payments are taxable wages.
What is the first and last day 75% rule?
Travel days pay 75% of the M&IE rate because part of the day is at home — GSA standard, adopted by most private policies.
Does per diem count as income for loans or 401(k)?
Generally no — tax-free stipends are not wages, so they miss 401(k) matches, Social Security credits, and most loan-qualifying income.
What is the one-year rule?
An assignment expected to exceed 12 months at one location stops being tax-deductible travel — per diem there becomes taxable from the point expectations changed.
✓ Formula verified • Last updated: August 20, 2026