FERS Supplement Calculator
OPM rules and SSA figures last checked October 2, 2026.
A federal retiree who starts an annuity in January 2026 at age 57, with a $1,800.00 age-62 Social Security estimate and 32 counted years of FERS service gets an estimated supplement of $1,440.00 a month for 52 months, before any earnings reduction.
Example shown. Enter your own details below.1. Your retirement
Immediate, unreduced retirement under 5 U.S.C. 8412(a). The supplement starts with your annuity.
Usually the month after your last day at work.
Military service does not count toward the supplement.
2. Your Social Security estimate
From your Social Security statement at ssa.gov. OPM computes its own figure from your federal pay only, so the statement is a starting point; see the note below the calculator.
3. Work after you retire (optional)
Wages plus net self-employment income. Your FERS annuity, TSP and investment income do not count.
SSA's 2027 figure is $25,560. Later years are not announced yet.
How we got this (example: born April 10, 1968, $1,800 estimate, 31 years 7 months, annuity from January 2026)
- 31 years 7 months of FERS civilian service counts as 32 years: the law rounds to the nearest whole year (a half year rounds up) and stops at 40. (5 U.S.C. 8421)
- Your age-62 Social Security estimate times your share of a 40-year career: $1,800.00 × 32 years ÷ 40 years = $1,440.00 a month (rounded to the cent) (OPM)
- It is paid from Jan 2026 through Apr 2030, the last month before you could draw Social Security at 62, which is 52 months: $1,440.00 a month × 52 months = $74,880 (shown to the nearest dollar)
- No work income after retiring is entered, so the earnings test takes nothing off and the total stays $74,880. (5 U.S.C. 8421a)
The idea behind it: OPM works out the supplement as if you were already 62 and drawing Social Security, then pays the part that matches your FERS career: 40 years gets the whole age-62 amount, 30 years gets three quarters of it. It stops once you could draw Social Security at 62, no later than the month you turn 62.
Enter your date of birth, annuity start month and age-62 estimate to see your supplement.
Your age-62 Social Security estimate times your FERS years over 40, paid from retirement to 62. Add any work income to see what the earnings test takes and in which months.
An estimate for planning, not advice and not an OPM determination. Your agency's benefits officer or OPM decides your eligibility, your creditable service and the amount. If a decision depends on the number, get it from them in writing.
How this is calculated
Monthly supplement = Social Security benefit at 62 x (years of FERS civilian service / 40)
- Benefit at 62: OPM figures it "as if you were age 62, fully insured for a Social Security benefit when the supplement begins and had applied for Social Security benefits," estimating a full 40-year career.
- Years: rounded to the nearest whole year, with a half year rounding up, and never more than 40 (5 U.S.C. 8421(b)(3)). So 31 years and 7 months counts as 32; 31 years and 5 months counts as 31.
- Paid: monthly from the start of the supplement through the month you turn 62, or the month before if your birthday is on the 1st or 2nd (Social Security counts you as reaching an age the day before your birthday, 20 CFR 404.2).
Example: an age-62 estimate of $1,800.00 and 31 years, 7 months of FERS service gives $1,800.00 x 32 / 40 = $1,440.00 a month. Someone born in April 1968 (MRA 56 years, 8 months) who retires with an annuity starting Jan 2026 is paid through Apr 2030: 52 months, $74,880 before any earnings reduction.
Why your Social Security statement is only a starting point
The calculator asks for the age-62 figure on your Social Security statement because it is the number you can get today. OPM does not use that number. Under 5 U.S.C. 8421(b)(2), OPM builds its own estimate from your federal basic pay only, and counts the years after you leave federal service as zero. Your statement is built from your whole earnings record, including any jobs outside the government. So OPM's figure can differ from the statement, in either direction. Ask your benefits officer for OPM's projection before you set a retirement date, or run the calculator with a lower and a higher figure to see the range.
The earnings test, step by step
If you work after retiring, 5 U.S.C. 8421a reduces the supplement this way:
- Take your wages plus net self-employment income for a calendar year, counting only the months you were entitled to the supplement.
- Subtract that year's Social Security exempt amount ($23,400 for 2025, $24,480 for 2026, $25,560 for 2027).
- Half of what is left is the reduction, but no more than the supplement you were owed for that year.
- It is spread over the 12 months starting the following July. No month loses more than the full monthly supplement, and months after you turn 62 drop out.
Continuing the example: earning $40,000 a year from January 2026 gives ($40,000 - $24,480) / 2 = $7,760 for 2026, taken as $646.67 a month from Jul 2027 through June 2028. Over the whole supplement period the earnings test takes $22,200 of $74,880 if that income continues and the exempt amount stayed at $25,560 after 2027; SSA says the amounts generally increase each year, which would make the cut smaller.
The timing catches people out. The first year of retirement is usually reduced by nothing, because the reduction is based on the previous year. Then a July arrives and the payment drops. OPM says you must report your earnings to OPM while you receive the supplement, and it sends instructions once payments start.
Where the numbers come from
The supplement formula, the service rounding and the age-62 end date come from 5 U.S.C. 8421 and OPM's FERS Types of Retirement page (checked Oct 2, 2026). The earnings test follows 5 U.S.C. 8421a (checked Oct 2, 2026). The exempt amounts, $23,400 for 2025, $24,480 for 2026 and $25,560 for 2027, are SSA's published figures (checked Oct 19, 2026). The calculator assumes your age-62 estimate and your civilian service are entered correctly, and assumes the 2027 exempt amount continues unless you enter another.
What this calculator leaves out
- Cost-of-living adjustments, federal and state tax, and survivor or court-ordered deductions.
- OPM's own rounding of the payment.
- Earnings that are uneven through the year: we spread each year's earnings evenly over its months when only part of the year counts.
- Your TSP and FEGLI. Those are separate calculations.
Before you set a retirement date, ask your agency benefits officer or OPM for your official supplement estimate in writing.
Who gets the supplement, and from when
| Retirement | Age and service | Supplement |
|---|---|---|
| MRA with 30 years | MRA, 30 years | From the annuity start |
| Age 60 | 60, 20 years | From the annuity start |
| Special provisions (LEO, firefighter, ATC, CBP officer, nuclear materials courier, Capitol or Supreme Court Police) | 50 with 20 years, or any age with 25 years | From the annuity start; earnings test ignores earnings before your MRA |
| Involuntary or early-out (VERA) | 50 with 20 years, or any age with 25 years | Only from your MRA |
| MRA+10, deferred, disability | Various | None |
| Age 62 or older | 62, 5 years | None (Social Security instead) |
From OPM's FERS Types of Retirement page and 5 U.S.C. 8412, 8414 and 8421.
Minimum retirement age (MRA)
| Year of birth | MRA |
|---|---|
| Before 1948 | 55 years |
| 1948 | 55 years, 2 months |
| 1949 | 55 years, 4 months |
| 1950 | 55 years, 6 months |
| 1951 | 55 years, 8 months |
| 1952 | 55 years, 10 months |
| 1953 to 1964 | 56 years |
| 1965 | 56 years, 2 months |
| 1966 | 56 years, 4 months |
| 1967 | 56 years, 6 months |
| 1968 | 56 years, 8 months |
| 1969 | 56 years, 10 months |
| 1970 or later | 57 years |
OPM's table, checked October 2, 2026.
Why we built it this way
A first-page supplement calculator we examined in October 2026 applies the 2026 earnings limit without saying which year's earnings count or when the cut starts, and takes whole years only, where the statute rounds 6 months or more up. Those details decide how much you actually receive in a given year, so this one models them and shows each step.
Questions people ask
How is the FERS supplement calculated?
OPM estimates the Social Security benefit you would get at 62 for your federal civilian career and multiplies it by your years of FERS civilian service divided by 40. OPM's own example: a $1,000 estimate and 30 years gives $1,000 x 30/40 = $750 a month. The law rounds service to the nearest whole year (half a year rounds up) and caps the fraction at 40/40.
Who gets the FERS supplement?
People who retire on an immediate annuity that is not reduced for age: MRA with 30 years, age 60 with 20 years, and special-provision retirees such as law enforcement officers, firefighters and air traffic controllers. Involuntary and early-out (VERA) retirees get it too, but only once they reach their MRA. OPM says there is no supplement with a deferred, disability or MRA+10 retirement.
When does the supplement stop?
No later than the last day of the month you turn 62, under 5 U.S.C. 8421(a)(3)(B). If your birthday is on the 1st or 2nd, it ends a month earlier, because Social Security treats you as reaching 62 the day before your birthday (20 CFR 404.2) and you can be entitled to Social Security for that whole month. It does not continue just because you wait to claim Social Security later.
How much can I earn before the supplement is reduced?
The Social Security exempt amount for the year: $25,560 for 2027 (SSA). For every $2 of wages or net self-employment income over that, $1 comes off the supplement. The reduction is based on the year before and starts in July: earnings in 2027 reduce payments from July 2028 through June 2029. Your FERS annuity, TSP withdrawals and investment income are not earnings for this test.
Does the earnings test apply to law enforcement officers and firefighters?
Not before your MRA. 5 U.S.C. 8421a(b)(4)(B)(ii) says earnings from before you reach the minimum retirement age do not count for special-provision retirees (law enforcement, firefighters, Capitol and Supreme Court Police, nuclear materials couriers, CBP officers and air traffic controllers). Earnings after your MRA do count. One more exception, in 8421a(c): retired air traffic controllers are outside the earnings test while they work as FAA-contract air traffic control instructors or supervisors, or as contract air traffic controllers.
Does military service count toward the supplement?
No. The statute defines service for the supplement to exclude military service (5 U.S.C. 8421(b)(4)(C)), even if you bought it back for your annuity. Enter only your civilian FERS years.
Can the earnings test take the whole supplement?
Yes. OPM says your earnings "may cause the supplement to be reduced to $0." It never reduces the rest of your FERS annuity. The law also caps a year's reduction at the supplement you were owed for the year the money was earned.
Official sources
- OPM: FERS Types of Retirement (annuity supplement eligibility, computation, earnings test, MRA table; checked Oct 2, 2026)
- 5 U.S.C. 8421, Annuity supplement (Cornell LII; checked Oct 2, 2026)
- 5 U.S.C. 8421a, Reductions on account of earnings (Cornell LII; checked Oct 2, 2026)
- 5 U.S.C. 8412, Immediate retirement (Cornell LII; checked Oct 2, 2026)
- 5 U.S.C. 8414, Early retirement (Cornell LII; checked Oct 2, 2026)
- SSA: Exempt Amounts Under the Earnings Test (checked Oct 19, 2026)
- 20 CFR 404.2, when you attain an age (eCFR; checked Oct 2, 2026)
- 20 CFR 404.311, when Social Security retirement entitlement begins (eCFR; checked Oct 2, 2026)
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