Estimate your FERS basic annuity (pension) from your high-3 salary, years of service and retirement age.
Basic formula (OPM): High-3 × years of service × multiplier. The multiplier is 1%, or 1.1% if you retire at age 62 or older with at least 20 years of service. Service counts in full years and months; extra days are dropped.
MRA+10: If you retire at your Minimum Retirement Age (MRA) with 10 to 29 years of service, and you aren't 60+ with 20 years, your annuity is reduced by 5% for each year you are under 62 (5/12 of 1% per month). The MRA is 55 to 57, depending on your birth year. You can postpone the start date to reduce or avoid this reduction (not modeled here).
Special provisions (LEO, firefighter, air traffic controller): 1.7% × high-3 × first 20 years, plus 1% × high-3 × service over 20 years. These employees can retire at age 50 with 20 years, or at any age with 25 years, without the MRA+10 reduction.
Not included: the FERS annuity supplement, COLAs, survivor benefit reductions, part-time service, unused sick leave credit, military buyback and deposit or redeposit rules. Sources: OPM "FERS Computation" and "Eligibility" pages (opm.gov/retirement-center).