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, such as a conference lunch or 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.