About the Per Diem Calculator
This per diem calculator totals the daily travel allowance for a business trip. Enter the number of calendar days you are away, the nights you need a hotel, the nightly lodging rate and the daily meals and incidental expenses (M&IE) rate, and it returns the maximum lodging reimbursement, the M&IE allowance and the combined per diem.
It follows the method used by the US federal travel regulations and most corporate travel policies that copy them: lodging is paid per night, while M&IE is paid per day and the first and last days of travel are paid at 75% of the full daily rate. If your employer, a conference or a hotel provides some meals, subtract their value so you are not paid twice.
Use it to budget a trip, check an expense report, or estimate what a client or grant will reimburse. Rates vary by city and by fiscal year, so look up the rate for your destination (for example on the GSA per diem site for US federal travel) and enter it; the defaults use the GSA standard CONUS rate for fiscal year 2026 (1 October 2025 to 30 September 2026) of $110 lodging and $68 M&IE. GSA resets rates every 1 October, so check the current year's figure for trips after that date.
With the default inputs, the total per diem is $746.00. Change any value above to recalculate instantly.
How to use the per diem calculator
- 1Enter the number of calendar days, counting departure and return days.
- 2Enter how many nights you need lodging.
- 3Look up the lodging and M&IE rates for your destination and enter them.
- 4Keep 75% for travel days or change it to match your policy.
- 5Add the value of any meals provided and read the total per diem.
Formula and method
Lodging is reimbursed per night, so the lodging allowance is the number of nights multiplied by the nightly lodging rate (actual cost up to that maximum in most policies). Meals and incidental expenses are paid per calendar day: every full day earns the whole M&IE rate, while the departure and return days earn a reduced percentage — 75% under US federal travel rules.
A one-day trip counts as a single travel day. (Under the Federal Travel Regulation, same-day trips of 12 hours or less usually earn no M&IE at all; set the percentage to 0 if that applies to you.) The value of any meals provided to you is then subtracted from the M&IE total. The calculator assumes one lodging rate and one M&IE rate for the whole trip; if you visit several cities, run it once per location.
- N
- Nights of lodging
- L
- Lodging rate per night
- F
- Full days (calendar days − 2)
- T
- Travel days (2, or 1 for a same-day trip)
- M
- Daily M&IE rate
- p
- Travel-day percentage (e.g. 75%)
- D
- Value of provided meals
Worked examples
5-day trip at the GSA standard rate
Four nights at $110 is $440 of lodging. Three full days at $68 is $204, and the two travel days at 75% ($51 each) add $102, for $306 of M&IE. The total per diem is $746.
Week in a high-cost city with a conference lunch
Six nights at $289 gives $1,734 of lodging. M&IE is 5 × $92 + 2 × $69 = $598, minus a $20 provided lunch, leaving $578. The trip allowance is $2,312.
Overnight trip
Both days are travel days, so M&IE is 2 × 75% × $79 = $118.50. Add one night at $150 for a total of $268.50.
Frequently asked questions
What is a per diem?+
A per diem is a fixed daily allowance an employer pays to cover lodging, meals and incidental costs while an employee travels for work, instead of reimbursing every receipt for meals.
Why are the first and last days paid at 75%?+
US federal travel regulations pay 75% of the M&IE rate on the day you leave and the day you return because you are only travelling for part of those days. Many private employers use the same rule.
Where do I find per diem rates?+
For US federal travel, GSA publishes lodging and M&IE rates for every county in the continental US each fiscal year; the State Department and Defense Department publish rates for foreign and non-CONUS locations. Your company policy may set its own rates.
Are per diem payments taxable?+
In the US, per diem paid under an accountable plan at or below the federal rate is generally not taxable wages if you substantiate time, place and business purpose. Amounts above the federal rate, or paid without substantiation, are usually taxable.
What counts as incidental expenses?+
Under federal rules, incidental expenses are fees and tips to porters, baggage carriers and hotel staff. Taxis, parking and airfare are reimbursed separately as transportation costs, not from the M&IE rate.
Tax results are estimates based on published rules and simplified assumptions. They are not tax advice — check official guidance or a tax professional for your situation.