Here is a great tool offered by the
The United States Geological Survey (USGS.GOV) the Get a rough estimate of the Federal annuity you would be entitled to on the day of your retirement. Please note: this calculator is an estimate and should not be used as an exact calculation of your retirement benefits. For a more detailed and more precise estimate, please contact your agency's personnel office. Click the appropriate link below to visit your retirement category:
FERS Retirement CalculatorCSRS Retirement Calculator.