How to Calculate Your FERS Disability

by Jimmy Boyd ; Updated July 27, 2017

The United States Office of Personnel Management (OPM) administers the Federal Employees Retirement System (FERS). Federal employees who have a qualifying disability can qualify for FERS disability benefits. The amount of the benefit depends on an employee's age and other factors. Disabled employees need to learn all the factors and formulas involved in computing FERS benefits. They can then calculate their FERS disability payments.

Step 1

Determine your high-three average salary. This figure is your highest average basic salary over any three consecutive years of federal employment. Average all of your time in federal service if you have less than three years of service. Do not include any bonuses or overtime.

Step 2

Access the FERS retirement eligibility page (see References). Use the first table to determine your minimum retirement age. Look at the "Immediate Retirement" table and use your age and number of years of service to determine if you are eligible for immediate retirement. Use the other tables to determine if you are eligible for early or deferred retirement.

Step 3

Multiply your high-three average salary by 1 percent for each year of service if you are at least age 62 and have less than 20 years of service. Multiply by 1.1 percent if you are at least 62 and have at least 20 years of service. This FERS disability is the standard retirement even without a disability and does not change. Use this same formula if you are under 62 but qualify for immediate voluntary retirement.

Step 4

Calculate your first 12 months of FERS retirement benefits if you are under age 62 and not qualified for immediate voluntary retirement. Multiply your high-three average salary by 60 percent and subtract all of your eligible monthly social security benefits. This is your entire payment for the first 12 months. However, use the higher of this amount and any other annuity you have earned through FERS.

Step 5

Determine your retirement benefits after the first 12 months. This benefit amount continues until you reach the age of 62. Multiply your average high-three salary by 40 percent. Subtract any eligible social security payments for any month in which you are entitled to social security. Your disability during this time period is the higher of this amount and any other earned annuity in the FERS retirement system.

Step 6

Figure out your disability payments starting at age 62. Increase your years of actual service by the time between your disability retirement and the age of 62. Add cost-of-living adjustments provided over that same time period to your high-three salary. Multiply that high-three salary by 1 percent for each year of service if you have less than 20 years. Multiply by 1.1 percent if you have at least 20 years.


  • Increase your disability payments by any annual cost-of-living adjustments. The federal government provides this adjustment as the cost of living increases.


  • Reduce your payments for any survivor benefits. Subtract 10 percent if your elected survivor benefits equal 50 percent of your benefits. Subtract 5 percent if you chose 25 percent as the amount for survivor benefits.

    Do not forget to apply for any social security benefits with the Social Security Administration. OPM can reduce disability payments even if you fail to apply for eligible benefits.

About the Author

Jimmy Boyd has a law degree from Thomas M. Cooley Law School. He has been writing articles on law and a variety of other topics since 2004. His work appears at, eHow and

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