Finding the Right Per Diem Rate
Your lodging and meal deduction is capped at the federal per diem rate for the place you performed duty — not at what you actually spent. Using the wrong rate is the most common source of an overstated deduction.
Two separate numbers
Federal per diem has two components, and they are capped separately:
- Lodging — a maximum nightly rate for your duty location.
- M&IE — meals and incidental expenses, a flat daily amount.
Lodging varies enormously by city and by month. M&IE varies far less. Both are published by the General Services Administration and both change every federal fiscal year, which begins October 1.
Where to look them up
Rates are free to look up at gsa.gov/travel/plan-book/per-diem-rates. Enter the city and state of your duty location, or the ZIP code if the city is ambiguous.
If your location is not listed
Most of the country is not individually listed. Anywhere without a specific listing falls under the standard CONUS rate, which is the default nationwide figure. Our calculator pre-fills the standard CONUS figures so you have a reasonable starting point, but you should replace them with your actual location's rate if it is listed separately.
Which fiscal year applies
Per diem rates are set by federal fiscal year, running October 1 through September 30. A drill weekend in November 2025 uses the FY2026 rate, not the FY2025 rate, even though the calendar year is 2025. If your duty dates span the October 1 boundary, split them and use each period's rate.
The 50 percent limit on meals
Meals get one extra haircut that lodging does not. After you apply the M&IE per diem cap, you may deduct only 50 percent of that amount. Lodging is not subject to this limit.
First and last day of travel
Federal travel rules generally allow only three quarters of the M&IE rate on the first and last day of a trip, since you are not away for the full day. Applying that reduction is the conservative and defensible approach.
Actual cost versus the cap
You deduct the lower of what you actually paid or the per diem cap. Spending $200 on a hotel where the lodging rate is $110 means you deduct $110. Spending $80 where the rate is $110 means you deduct $80 — you cannot claim the difference.
| Scenario | Lodging rate | You paid | You deduct |
|---|---|---|---|
| Expensive hotel | $110 | $200 | $110 |
| Budget motel | $110 | $80 | $80 |
| Stayed with family, paid nothing | $110 | $0 | $0 |
That last row matters: the per diem cap is a ceiling, not an allowance. If you did not spend the money, there is nothing to deduct.