U.S. Office of Personnel Management - Ensuring the Federal Government has an effective civilian workforce
Computation of Interest on Back Pay System
This program computes the amount of interest due on disbursements of back pay issued under the authority of 5 U.S.C. 5596.
Back Pay Interest Rates
Back pay interest is computed using certain interest rates established by the Secretary of the Treasury under 26 U.S.C. 6621(a)(1). The interest rate is updated quarterly (January 1, April 1, July 1, and October 1). OPM maintains a web page that contains a table of these quarterly interest rates.
Go to Quarterly Back Pay Interest Rates
Program Downloading Instructions
We strongly suggest that users view and print the "Read Me" file below before attempting to download and operate the back pay interest program.
Download the Program 
[6.9 MB Self-Extracting ZIP File]
OPM Computation of Interest on Back Pay System Help Documents
| File Name | Size | Description | File Date |
|---|---|---|---|
| OnLineDoc.htm | 30 KB | On-Line User Documentation | 5/20/99 |
| IntRateHow.htm | 5 KB | How to Get Latest IRS Interest Rates and Update the Interest Table in the OPM Back Pay Interest System | 5/13/99 |
| BackPayLaw.htm | 7 KB | Back Pay Law, Section 5596, of Title 5, United States Code | 5/13/99 |
| BackPayReg.htm | 25 KB | Back Pay Regulations, 5 CFR 550, Subpart H - Back Pay | 1/18/00 |
| OPMInstr.htm | 21 KB | Historical FPM Letter 550-7 | 5/13/99 |
| FAQ.htm | 7 KB | Frequently Asked Questions | 5/13/99 |
The latest versions of the Help document files are shown in the table above. Click on the filename to view and/or download the file. When these Help documents are updated, you will need to download and copy any updated version into the folder on your computer containing the OPM Back Pay Interest System (by default: c:\ProgramFiles\OPM Back Pay Interest System).
You can compare the file dates of the Help documents on your computer to the dates in the above table by doing the following:
- Run Windows Explorer
- Select the 'Detailed View' (View-Details)
- Locate the 'OPM Back Pay Interest System' folder
- Find file dates in the 'Modified' Column.
Help document updated: Back Pay Regulations - 1/18/00
U.S. Office of Personnel Management 1900 E Street NW, Washington, DC 20415 | (202) 606-1800 | TTY (202) 606-2532