Per Diem Calculator
Enter the daily rate and trip length. Get the total allowance with first/last-day proration — and the pocketable difference if you spend under it.
| Full days | — |
| Travel days (75%) | — |
| If you spend $55/day, you keep | — |
How per diem works
Total = Rate × full days + Rate × 75% × travel days
Per diem replaces receipt-by-receipt expense reports with a flat daily allowance for meals and incidentals (M&IE). US federal GSA rates — the benchmark most companies copy — run about $68 standard to $92 in high-cost cities, with the first and last travel day paid at 75%.
The quietly great part: keeping the difference
Under most corporate and all federal per diem policies, the allowance is yours regardless of actual spending — spend $55/day against a $79 rate on the example trip and about $110 stays in your pocket, tax-free (per diem within federal rates is not taxable income to employees). Frequent travelers quietly bank $1,000+/year this way. The reverse also holds: expensive-city appetites above the rate come out of your own wallet.
Rules that trip people up
- Provided meals reduce the allowance: conference lunch or hotel breakfast usually means deducting that meal’s share.
- Lodging is separate: M&IE per diem covers food and incidentals; hotels are booked or reimbursed separately (or under a lodging per diem with its own GSA cap).
- Self-employed: can use M&IE per diem rates for travel meal deductions (50% deductible), but not the lodging per diem — real hotel receipts required.
Frequently asked questions
How is per diem calculated for travel days?
The standard (GSA) method pays 75% of the M&IE rate on the first and last day, full rate for days in between. A 6-day trip at $79 = 4 full days + 2 × $59.25 ≈ $434.50.
Do I keep unspent per diem?
Under most flat per diem policies, yes — it is an allowance, not a reimbursement, and within federal rates it is not taxed. Some employers instead reimburse actuals up to a cap; check which model applies.
What is the current standard per diem rate?
The US GSA standard M&IE rate sits in the high $60s–low $70s, with major cities up to the low $90s. Rates update every October; gsa.gov has the official lookup by destination.
Is per diem taxable?
Not when paid under an accountable plan at or below federal rates with a business purpose. Amounts above the federal rate, or allowances without required trip documentation, become taxable wages.
All Everyday Money calculators
50/30/20 Budget · Bill Split · Cash Back vs Points · Christmas Budget · Cost Per Wear · Discount · Electricity Cost · Foreign Transaction Fee · Gas Cost · Grocery Budget · Habit Cost · Percentage · Price Per Square Foot · Rent Affordability · Rent Split by Room · Sales Tax · Subscription Cost · Tip · Tip Pooling · Trip Budget · Unit Price · VAT · Wedding Budget · Zakat
Last updated: 2026-07-08