FERS Retirement Calculator — Basic Annuity Estimate

How to use

1. Find your high-3: the highest 36 consecutive months of basic pay — usually your last three years.
2. Total your creditable service years, including sick-leave credit where applicable.
3. Enter your planned retirement age and whether you elect the survivor annuity.
4. Read the annual and monthly annuity, the multiplier used and the TSP reminder.

General information only — not medical, financial or legal advice. Figures cross-checked against public official sources (IRS / HMRC / NHS / WHO guidance); content last reviewed September 2026. For decisions that matter, confirm with a licensed professional in your country.

About this tool

Your FERS basic annuity follows a short formula, but the details around it decide the real number. This calculator applies the formula directly: high-3 average salary × years of creditable service × 1%, stepping up to 1.1% if you retire at 62 or later with at least 20 years of service. It shows the annual and monthly gross benefit, your replacement rate as a share of high-3, and the reduction if you elect the full survivor annuity for a spouse. Where the formula ends, the notes begin: MRA rules, age reductions, deposits and prorations are flagged rather than guessed, and the TSP leg — for most retirees the largest asset — is pointed to rather than modeled blind. Use it to sanity-check a retirement board estimate or pick a date. This is an educational estimate, not professional advice; confirm with your agency benefits officer before you commit.

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