This FERS Annuity and Supplement Estimator dishes out a ballpark figure for your potential FERS Annuity and Supplement based on the info you punch in. If you’re not eligible, you’ll still get a deferred retirement estimate to toy with. This tool is just for kicks and learning, not the final word. Always double-check with your HR or OPM for the real deal.
Important Note: To use this calculator, you will need to know your Social Security Administration estimate for starting your benefits at age 62.
If you do not have this information, please obtain it before proceeding.
Gross estimate before federal/state taxes & deductions
FERS Annuity
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/mo · — /yr
FERS Supplement
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/mo · — /yr
Social Security (age 62+)
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/mo · — /yr
FERS Supplement — Ended at 62
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The FERS Supplement stops at age 62 when Social Security eligibility begins. Your actual SS benefit may differ — check your SSA.gov statement.
Combined Annual (Annuity + Supplement)
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Calculation details
FERS Annuity Formula
Your annuity multiplier depends on your employment category and your age and years of service at retirement.
Traditional FERS
Standard
1.0% × High-3 × Years
All scenarios not covered by the enhanced rate
Enhanced rate
1.1% × High-3 × Years
Age 62+ and 20+ years of creditable service
Special Category (LEO · FF · ATC · CBPO)
First 20 years
1.7% × High-3 × 20
Applied to the first 20 years only
Years beyond 20
1.0% × High-3 × Extra Years
Each year of service past 20
High-3 is the average of your highest 3 consecutive years of base pay — typically your last 3 years.
Sick leave is converted to months (174 hours = 1 month) and added to your creditable service for the annuity calculation — but not for the Supplement.
Military buyback years count toward your annuity and eligibility but not toward the FERS Supplement.
FERS Supplement
The FERS Supplement bridges the gap between your retirement date and age 62 when Social Security begins. It approximates the Social Security benefit you earned while covered under FERS, prorated by your civilian service.
(Civilian FERS Years ÷ 40) × Estimated SS at 62
Only civilian FERS service counts — sick leave and military buyback years are excluded.
Service is capped at 40 years, so the factor (years ÷ 40) can never exceed 1.0 — the supplement can never exceed your full SSA estimate.
Payable on an immediate annuity before age 62: traditional FERS at MRA with 30+ years or age 60 with 20+ years; special category at age 50 with 20+ years or any age with 25+ years.
Subject to the Social Security earnings test — if you earn wages above the annual limit before age 62, the supplement is reduced $1 for every $2 over the threshold.
The supplement stops at age 62 regardless of whether you claim Social Security — at 62, actual SS eligibility begins.
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Disclaimer
This calculator is for informational and educational purposes only and provides a rough estimate of your FERS annuity and supplement. For precise calculations and personalized advice, consult your agency’s human resources office or a qualified financial advisor.
