Determine your High-3 average salary
Identify your total creditable FERS service
Convert unused sick leave to additional service credit, if applicable
Use the basic FERS annuity formula
Multiply 1% of your High-3 by your years of creditable service
Use 1.1% instead of 1% if you are age 62 or older with at least 20 years of service
Add any special category or enhanced service credit if applicable
Subtract any age reduction if you retire before the minimum retirement age and do not qualify for an unreduced annuity
Apply any survivor election reduction, if applicable
Apply any court-ordered or other deductions, if applicable
Add the FERS annuity supplement only if you qualify
Estimate your monthly annuity by dividing the annual amount by 12