Inputs you will enter
- Social Security estimate at 62The monthly figure from your Social Security statement at ssa.gov.
- FERS civilian serviceYears and months. Leave out military time.
- Date of birth and retirement dateTo check eligibility and count months to 62.
- Retirement typeMRA+30, 60+20, special provisions, early-out or discontinued service.
- Expected earnings after retiringOptional, for the earnings test.
- Annual exempt amountPrefilled with the Social Security figure and its as-of date; you can change it.
How we compute it
We divide your FERS civilian service, rounded down to whole years, by 40. We multiply that fraction by your Social Security estimate at 62 to get the monthly supplement. A full 40 years would equal the whole estimate; most people have fewer, so the supplement is a share of it.
If you enter earnings, we apply the earnings test as OPM describes it: the supplement is reduced $1 for every $2 of earnings above the Social Security annual exempt amount. Only wages and self-employment income count. Your annuity, TSP withdrawals and investment income do not.
For special provision retirees, the earnings test does not apply until you reach your MRA.
A worked example
Your Social Security statement shows $1,800 a month at 62, and you have 30 years of FERS civilian service. The estimate is 30 / 40 x $1,800 = $1,350 a month. If you retire at 57, that runs for about 60 months. Educational estimate on the assumptions shown.
What to do with your estimate
Add it to your FERS pension estimate for the years before 62, and check your earliest dates with the retirement date finder. The FERS supplement guide covers the rules in depth, and the Social Security guide covers what happens at 62.
Wondering whether working part time after you retire is worth the reduction?
FFEBA is an education organization. If you want someone to look at your own numbers, we can match you with a Federal Retirement Consultant (FRC), a professional trained on federal benefits. The FRC designation is listed with FINRA. The first review is free, nothing is booked until you choose a time, and you are never obligated to work with anyone we introduce. Get matched with an FRC.
Questions about this calculator
Who gets the FERS supplement?
FERS employees who retire on an immediate, unreduced annuity before 62: at their MRA with 30 years, at 60 with 20 years, or under special provisions. Early-out and involuntary retirees can receive it once they reach their MRA. MRA+10 and deferred retirees do not get it.
When does the FERS supplement stop?
It stops at the end of the month you turn 62, whether or not you claim Social Security then. It also stops or shrinks if your earnings from work exceed the Social Security annual exempt amount.
Does military service count toward the supplement?
No. Only FERS civilian service counts in the supplement formula, even if you bought back military time for your annuity.
Is the FERS supplement taxable?
Yes, the supplement is taxed as ordinary income at the federal level, like your annuity. State treatment varies. See our taxes guide for the state-by-state picture.
Does the FERS supplement get a COLA?
No. The supplement does not receive cost-of-living adjustments.
Reviewed by the FFEBA education team. Last reviewed October 2026.
Sources
- U.S. Office of Personnel Management, CSRS/FERS Handbook (FERS annuity supplement), retrieved 2026-07-05
- Social Security Administration, my Social Security statement, retrieved 2026-10-11
Every government figure on this page carries its source and retrieval date. Worked examples are educational estimates on the assumptions shown, not a projection of any person's benefit. FFEBA is an education organization, not a financial advisor.
