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Calculating Per Diem

Find out how to calculate per diem rates for university business travel.

Use the instructions below to estimate per diem rates. Actual per diem amounts are calculated when using MyTravel to claim expenses.

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  • Read Per Diem for Travel for an overview of meal and lodging expenses.
  • You can use MyTravel to claim most per diem expenses as they’re calculated automatically based on location and duration. See Using MyTravel.
  • For travel 29 days or less in the continental U.S., per diem does not apply. Use MyTravel to claim actual costs for lodging and Meals and Incidentals Expenses (M&IE) — not to exceed the allowable maximum.
    Note: Claiming per diem is limited to business travel and shouldn't be used to initiate payment that is compensation. For foreign travel, travelers should only claim actual travel expenses (e.g., subsistence and lodging) up to the per diem rate. Learn more about claiming actual expenses to save costs, or as an exception if costs exceed the allowable per diem.

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1. Calculate the number of days on travel status.

  • Calculate the number of hours on travel status for each location.
  • Divide the number of hours on travel status by 24 for each location.
    • Example: 756 hours of travel divided by 24 = 31.5 days of travel.
  • Round partial days to the nearest quarter.
    • Example: Round 33.69 days to 33.75.

2. Determine the per diem rate.

Find the appropriate per diem rate for each location.

3. Estimate the expenses.

  • You can estimate expenses based on the published per diem rate, but if actual expenses are below the published rate, actual must be claimed:
    • Number of days x per diem rate = total per diem for location
    • Add the totals for each location to determine the total per diem allowance for the travel event.
  • To  estimate expenses for long term trips (greater than 30 days and less than one year),the recommendation is to use the published rate with a 55% calculation:
    • Number of days x per diem rate x 55% = total per diem for location.
    • Add the totals for each location to determine the total per diem estimate for the travel event.
    Note: Receipts for lodging and meals are not required by UC San Diego Travel policy when claiming actuals up to per diem. Receipts for lodging and meals are required when actual expenses exceed the per diem rate due to special circumstances.

4. Deduct meal rates, if applicable.

  • For each meal or lodging provided at no charge during travel or paid as part of a registration fee, the daily per diem must be adjusted as follows:
    • Breakfast - 15%
    • Lunch - 25%
    • Dinner - 40%
    • Lodging - 100%
  • Use the "Adjustment of Per Diem due to meals and lodging provided without charge" in MyTravel to deduct such meals and lodging.

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Notice: UC San Diego travel policy, as published in Blink, is decisive. It has been adapted to UC San Diego's organization, delegation of authority, terminology, chart of accounts and processing applications. The source for UC San Diego travel policy is UC Travel Policy and Regulations (PDF).