Per Diem Calculator
Work out a business trip's per diem: M&IE with the 75% first/last day rule, lodging nights, meal deductions and a day-by-day breakdown.
Pick your travel dates and the rates — the allowance is recalculated as you type.
- Travel days
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- Nights (lodging)
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- M&IE allowance
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- Meal deductions
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- Lodging total
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- Total per traveller
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- Grand total
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| Day | Date | M&IE | Lodging | Day total |
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An estimate, not an expense-policy ruling. The built-in tiers are the U.S. GSA FY2025 CONUS M&IE rates with the standard $110 lodging rate; your employer, country or destination city may use different numbers — type them in. Everything is calculated in your browser.
How it works
A per diem is a flat daily allowance for business travel: one amount for meals and incidental expenses (M&IE) and one for lodging. This calculator follows the U.S. GSA / IRS method. Travel days are counted inclusively, so a trip from the 2nd to the 6th is five days, and lodging is paid per night — one fewer than the number of days, because you do not sleep at the destination on the day you travel home. M&IE on the first and last day is paid at 75% of the daily rate (the GSA "three-quarters rule"); a same-day trip with no overnight stay is also paid at 75%. Untick the box if your employer pays the full rate on every day.
Meals somebody else pays for — a conference lunch, a hotel breakfast — are deducted from the allowance. The deduction fields are pre-filled from the GSA FY2025 breakdown of the selected tier ($68 = $16 breakfast, $19 lunch, $28 dinner, $5 incidentals; the tiers run $68, $74, $80, $86 and $92). Note that under the Federal Travel Regulation the $5 incidental portion is still paid even when every meal is provided, so if that applies to you, lower the deduction amounts accordingly. The day-by-day table shows exactly how the total is built up, and the whole thing works offline: no accounts, no ads, and none of your travel dates leave the page.
Frequently asked questions
How is per diem calculated for travel days?
Count the travel days inclusively — 2 to 6 March is five days — and pay lodging per night, which is always one fewer than the number of days because you sleep at home the night you travel back. Meals and incidental expenses (M&IE) are paid at the full daily rate for the days in between, and at 75% of the rate on the first and last day. At the GSA FY2025 standard CONUS rates ($68 M&IE, $110 lodging) that five-day trip works out at 2 × $51 + 3 × $68 = $306 M&IE plus 4 × $110 = $440 lodging, so $746 in total.
Why is the first and last day only 75%?
Because you are not travelling for the whole of either day. The GSA's Federal Travel Regulation applies a flat three-quarters rule rather than making you prorate by the hour, and the IRS accepts the same treatment for accountable-plan reimbursements. A same-day trip with no overnight stay is also paid at 75%. If your employer pays the full rate every day, untick the 75% box and the calculator recomputes instantly.
What happens when a meal is provided?
A meal someone else pays for — a conference lunch, a hotel breakfast — is deducted from that day's M&IE. The calculator pre-fills the deduction amounts from the GSA FY2025 breakdown of the tier you pick ($68 splits into $16 breakfast, $19 lunch, $28 dinner and $5 incidentals), and the tiers run $68, $74, $80, $86 and $92. One nuance: the federal rules still pay the $5 incidental portion even when every meal is provided, so lower the deduction amounts if that applies to you. All the fields are editable, so non-US travellers can enter their own policy rates.