Where these rules come from — Federal Retirement Calculator

Federal Retirement Calculator implements published federal benefit rules. Every one is cited back to the agency that publishes it, with the full URL shown so you can check it without installing anything.

U.S. Office of Personnel Management (opm.gov)

FERS retirement — overview of the whole systemhttps://www.opm.gov/retirement-center/fers-information/

How the pension is computed — high-3 and the 1% / 1.1% multiplierhttps://www.opm.gov/retirement-center/fers-information/computation/

Retirement eligibility and the Minimum Retirement Agehttps://www.opm.gov/retirement-center/fers-information/eligibility/

Types of retirement, including MRA+10 and its reductionhttps://www.opm.gov/retirement-center/fers-information/types-of-retirement/

Creditable service — unused sick leave, military service, part-timehttps://www.opm.gov/retirement-center/fers-information/creditable-service/

The FERS retiree annuity supplement (CSRS/FERS Handbook, Chapter 51)https://www.opm.gov/retirement-center/publications-forms/csrsfers-handbook/c051.pdf

Cost-of-living adjustments and the reduced FERS COLA formulahttps://www.opm.gov/support/retirement/faq/cost-of-living-adjustments/

Survivor benefits and the survivor annuity electionhttps://www.opm.gov/retirement-center/survivor-benefits/

FEHB health coverage for annuitants and survivorshttps://www.opm.gov/healthcare-insurance/healthcare/reference-materials/reference/annuitants/

FEHB premium rates, published each yearhttps://www.opm.gov/healthcare-insurance/healthcare/plan-information/premiums/

FEGLI premiums for annuitants, by age band and post-65 electionhttps://www.opm.gov/healthcare-insurance/life-insurance/program-information/

General Schedule pay tables and locality rateshttps://www.opm.gov/policy-data-oversight/pay-leave/salaries-wages/

Thrift Savings Plan (tsp.gov)

The Thrift Savings Plan — official sitehttps://www.tsp.gov/

Contribution limits, agency matching, and catch-up contributionshttps://www.tsp.gov/making-contributions/contribution-limits/

Social Security Administration (ssa.gov)

Full retirement age and the reduction for claiming earlyhttps://www.ssa.gov/benefits/retirement/planner/agereduction.html

Delayed retirement credits for claiming after full retirement agehttps://www.ssa.gov/benefits/retirement/planner/delayret.html

Benefit amounts at every claiming age from 62 to 70https://www.ssa.gov/OACT/quickcalc/early_late.html

The earnings test — working while receiving benefitshttps://www.ssa.gov/benefits/retirement/planner/whileworking.html

Income taxes on your Social Security benefit, and withholding themhttps://www.ssa.gov/manage-benefits/request-withhold-taxes

Internal Revenue Service (irs.gov)

Revenue Procedure 2025-32 — the 2026 tax brackets and standard deductionhttps://www.irs.gov/pub/irs-drop/rp-25-32.pdf

Publication 505 — the additional standard deduction from age 65https://www.irs.gov/publications/p505

The enhanced deduction for seniorshttps://www.irs.gov/newsroom/check-your-eligibility-for-the-new-enhanced-deduction-for-seniors

Required minimum distributionshttps://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-required-minimum-distributions-rmds

Internal Revenue Bulletin 2024-33 — the age RMDs start: 73, or 75 if born in 1960 or laterhttps://www.irs.gov/irb/2024-33_IRB

Publication 590-B — the life expectancy tables used for RMDshttps://www.irs.gov/publications/p590b

Publication 915 — how much of a Social Security benefit is taxablehttps://www.irs.gov/publications/p915

Publication 969 — Health Savings Accounts, and paying Medicare premiums from onehttps://www.irs.gov/publications/p969

Revenue Procedure 2025-19 — the 2026 HSA contribution limitshttps://www.irs.gov/pub/irs-drop/rp-25-19.pdf

Centers for Medicare & Medicaid Services (cms.gov)

Medicare Part B premium and the IRMAA income surcharge, including the Part D adjustmenthttps://www.cms.gov/newsroom/fact-sheets/2026-medicare-parts-b-premiums-deductibles

What Medicare costs — enrolment, premiums and deductibleshttps://www.medicare.gov/basics/costs/medicare-costs

Every URL here was checked against the live site. If one stops working, tell us and it will be replaced rather than dropped.