For a typical Air Force TDY under the standard lodging-plus-per-diem method, your daily amount combines eligible actual lodging costs, up to the applicable limit, with the meals and incidental expenses allowance that applies to your trip. You do not automatically receive the maximum hotel amount just because it appears in a rate lookup.
That distinction answers many first-TDY questions: what you can budget for food, whether you keep the difference on a cheaper hotel, and why DTS may show a different amount than a general rate table. The governing starting point is the Joint Travel Regulations, paragraph 020301.
This guide covers routine, multiday TDY using that standard method. Trips of less than 24 hours have separate duration rules in JTR paragraph 020309 and Table 2-20; do not apply the four-day example below to a same-day trip. Actual expense allowances, field duty, leave, and other special circumstances need their own applicable rules.
The two parts of TDY per diem
| Part | How to think about it | What to check |
|---|---|---|
| Lodging | Reimbursement for eligible actual lodging costs, subject to the applicable limit | Actual nightly charge, authorized lodging arrangements, and any lower program limit |
| Meals and incidental expenses, or M&IE | The applicable daily allowance under the standard method | Location, meal status, travel days, and other required adjustments |
The lodging limit and M&IE rate are different components. A rate lookup helps identify the starting figures; your trip circumstances determine which figures apply. JTR paragraph 020301 establishes the basic calculation, and paragraph 020304 addresses M&IE. Current JTR
Do you keep unused per diem?
Lodging: If your eligible hotel charge is below the applicable limit, ordinary lodging reimbursement is based on the actual charge. The difference between that charge and the limit is not an additional hotel payment to you.
Meals and incidentals: Under standard M&IE rules, reimbursement does not require itemizing what you spent on each meal. Spending less than the applicable allowance does not, by itself, turn M&IE into an actual-cost reimbursement. However, you must use the correct meal status and report circumstances that affect the allowance. When an actual expense allowance is authorized or approved for some portion of M&IE, different documentation rules apply. See JTR paragraphs 020301 and 020304. Current JTR
The practical question is not simply whether you spent less. It is whether the amount claimed is the correct allowance for that day.
A four-day TDY example
Suppose a routine TDY has all of the following conditions:
- You depart Monday and return Thursday, with no additional stopovers.
- You have three eligible hotel nights at $90 per night.
- The applicable lodging limit is $100 per night.
- The applicable locality M&IE rate is $60.
- Tuesday and Wednesday qualify for the full locality M&IE rate.
- There is no leave, meal deduction, reduced rate, actual expense allowance, or other adjustment.
These are invented numbers for illustration, not current rates for a particular base. Taxes, transportation, other separately reimbursable expenses, and payment offsets are excluded.
| Day | Eligible lodging | M&IE | Example daily total |
|---|---|---|---|
| Monday, departure | $90 | $45 | $135 |
| Tuesday | $90 | $60 | $150 |
| Wednesday | $90 | $60 | $150 |
| Thursday, return | $0 | $45 | $45 |
| Total | $270 | $210 | $480 |
The hotel component is $270, not the $300 maximum for three nights. The example uses 75% of $60, or $45, for M&IE on the departure and return days. That travel-day percentage applies to M&IE, not to the hotel charge. DTMO travel-day guidance
The $480 is the example's lodging-plus-M&IE calculation. It is not a prediction of the amount that would be deposited into your personal bank account.
Why the first and last days are different
For the routine departure and return days described here, DTMO specifies 75% of the applicable M&IE rate, regardless of the time you leave or return. It also explains that government and proportional meal rates do not apply on those travel days. Stopovers can change which locality rate applies, so a more complicated itinerary needs a day-by-day check. DTMO per diem on travel days
Do not multiply every calendar day of the trip by a full M&IE rate without checking the travel days first.
Why your meal allowance may be lower than expected
The full locality meal rate is not the only meal rate. Depending on the circumstances, a member may have a government meal rate, proportional meal rate, or incidental-expense-only treatment.
For example, the standard government meal rate has specific conditions involving lodging, government dining availability, and direction in the travel authorization. Proportional meal rates also have defined conditions; they are not simply a percentage selected because you happened to buy fewer meals. JTR Table 2-17 lists the meal-rate categories and their application. DTMO meal-rate guidance, JTR paragraph 020304 and Table 2-17
If DTS shows less than you expected, check the meal status and the information in your authorization. If dining availability or provided meals differ from the planned circumstances, take the details to your travel support team instead of changing the rate based on a guess.
Why the lodging limit may be lower than the advertised per diem rate
A locality rate is not a promise that every hotel choice will be reimbursed at that amount. Under the Integrated Lodging Program, declining available required lodging without the applicable authorization can limit reimbursement to what the government would have paid for that lodging. That amount may be below the locality ceiling. DTMO lodging FAQ, reimbursement below per diem
Before booking, confirm the lodging process for your destination, the applicable limit, and what to do if the required lodging is unavailable. If available rooms cost more than expected, resolve the approval question before treating the higher amount as reimbursable.
Why your bank deposit may not match your voucher total
Travel reimbursement can include payment directly to your government travel card through split disbursement. DTMO directs travelers to review the amount going to the card vendor when preparing the voucher. That means looking only at your bank deposit can give you an incomplete picture of where the reimbursement went. DTMO cardholder guidance, Split Disbursement
Compare the approved voucher, payment distribution, and card account before concluding that money is missing. The per diem calculation and the destination of the payment are separate questions.
What to check before estimating your TDY money
- Confirm the official TDY location and dates.
- Find the applicable lodging and M&IE figures using the official per diem resources.
- Check whether your lodging arrangements impose a different applicable limit.
- Check meal status and any special conditions in the authorization.
- Separate departure, return, and full TDY days.
- Use actual eligible hotel charges when estimating lodging reimbursement.
- Keep separately claimed expenses and payment distribution separate from this calculation.
If your estimate differs from DTS, identify which day or component differs. A question such as “Which meal status applies on Tuesday?” is more useful than comparing only the total.
Prepare with your class as well as your travel office
Official guidance answers the allowance question. Classmates can help identify practical preparation questions: what dining arrangements need clarification, what to bring for a multiweek stay, and which arrival logistics still need attention.
TDY Spy is being built to connect Air Force members preparing for the same class. Once you understand your allowance, classmates can help you identify practical questions about dining, lodging amenities and arrival plans. Your travel office remains the source for entitlement decisions.
Common TDY per diem questions
Is lodging included in per diem?
Yes, lodging is one component. Under the standard method, it is based on eligible actual lodging costs up to the applicable limit, while M&IE uses its applicable allowance. See the calculation above.
Do I need receipts for every meal?
Standard M&IE does not require itemization or receipts under JTR paragraph 020304. An actual expense allowance for some portion of M&IE changes that treatment. This does not remove documentation requirements for lodging or separately claimed expenses.
Can I use my classmate's per diem amount as my estimate?
Use it as a reason to compare the relevant facts, not as proof of your entitlement. Travel dates, lodging arrangements, meal status, and other circumstances can differ. Check the specific components of your own trip.