Reviewed & updated: August 26, 2026
How the Federal Pension Formula Works
Quick answer: a federal pension (annuity) is computed from three things — your retirement system, your high-3 average salary (generally your highest-paid 36 consecutive months of basic pay), and your years of creditable service. Under the Federal Employees Retirement System (FERS), the basic annuity is generally 1% of high-3 per year of service (1.1% at age 62 or later with 20+ years). Under the Civil Service Retirement System (CSRS), the formula is tiered: 1.5% for the first 5 years, 1.75% for the next 5, and 2% beyond 10, generally capped at 80% of high-3. The estimator below applies exactly those published formulas to the numbers you enter — nothing more.
Looking for when you may be able to retire instead of how much the formula produces? That’s a different question — use our retirement timing calculator for timeline education.
This is an educational estimate
Use the published formula as a worksheet
Write down your retirement plan, high-3 average salary, completed creditable service, and age at retirement. For FERS, multiply high-3 by service and generally by 1%, or 1.1% at age 62 or later with at least 20 years. CSRS uses its tiered percentages instead.
This worksheet is only a formula illustration. It does not settle reductions, survivor elections, supplements, deposits, special provisions, taxes, or other factors that can change an official estimate.



