Per Diem (GSA) Estimate Calculator
Example: Number of nights: 4 · Lodging rate per night: 178 $ · M&IE rate per day: 79 $
| Total per diem | $1,068 |
| Lodging total | $712 |
| Meals & incidentals total | $356 |
Worked example
A trip with 4 nights spans 5 travel days. Lodging is only paid for the 4 nights: 4 times $178 is $712. For meals, the 3 middle days pay the full $79 ($237), while the first and last days pay 75% of $79, or $59.25 each ($118.50), for an M&IE total of about $355.50. Altogether the per diem is roughly $1,067.50. Forgetting the 75% rule would overstate the meals by nearly $40.
Frequently asked questions
Where do I find the correct GSA rates?
The U.S. General Services Administration publishes per diem lodging and M&IE rates by city and county, updated each fiscal year. Look up your destination on the GSA per diem site and enter those exact figures for an accurate estimate.
Why are the first and last days only 75%?
Travelers usually depart or return partway through those days, so a full day of meals is not warranted. Federal rules set travel-day M&IE at 75% of the daily rate, and this tool applies that automatically for the first and last day.
Is lodging paid for the last day?
No. Lodging per diem is paid per night, so a trip with 4 nights and 5 days reimburses 4 nights of lodging. The extra travel day only affects meals and incidentals, not lodging.
Does per diem cover the actual hotel bill?
Per diem caps what you can be reimbursed; if your hotel costs less, you are reimbursed the lower actual amount under most policies, and if it costs more, you may cover the difference. Some agencies allow exceptions for high-cost cities.