Definition. The total sum of money due for the purchase of a good or service that must be paid by the set due date. In relation to taxes, the money owed to the government when required tax amount totals a greater number than total tax payments previously made.efinition. The total sum of money due for the purchase of a good or service that must be paid by the set due date. In relation to taxes, the money owed to the government when required tax amount totals a greater number than total tax payments previously made.
The Internal Revenue Service has set the special per diem rates starting Oct. 1, 2015, which taxpayers can use to substantiate the amount of expenses for lodging, meals, and incidental expenses when traveling away from home.
Per Diem Rates. Calculation of travel per diem rates within the Federal government is a shared responsibility of three organizations: 1  The General Services Administration (GSA) prescribes rates for the Continental U.S. GSA updates the Continental U.S. rates once a year, or as necessary. Normally the rates are updated at the start of the new fiscal year. 2  If a uniformed member or DoD federal civilian has questions regarding the adequacy of per diem rates, please see Per Diem Rate Review under Frequently Asked Questions (FAQs) for appropriate procedures.