FERS Annuity Calculator

How this is calculated

The FERS basic annuity is one formula with a small number of adjustments bolted onto it. Written out:

high-3 average salary × factor × years of creditable service

The factor

The factor is 1% per year of service. It rises to 1.1% in one case only: you are 62 or older when you separate and you have at least 20 years of service. Both conditions, at separation. That single change is worth 10% of the whole annuity, which is why the calculator names it explicitly rather than folding it in silently.

When you can start collecting

An immediate annuity begins the month after you separate. You qualify at age 62 with 5 years of service, at 60 with 20, or at your minimum retirement age (MRA) with 30. A fourth combination — MRA with at least 10 years — also pays immediately, but permanently reduced by 5% for each year you are under 62, prorated by month. Your MRA depends on your year of birth: 55 for those born before 1948, rising in two-month steps to 57 for anyone born in 1970 or later.

With at least 5 years of service but none of those combinations met, the pension is still earned — it just sits as a deferred annuity until you turn 62. Under 5 years, no annuity is payable at all.

Unused sick leave

Sick leave you never used is converted to service credit at 2,087 hours per year, on a 360-day service year. Two limits matter and are both modelled here: it is added after eligibility is decided, so it can never make you eligible to retire earlier, and it cannot carry you across the 20-year threshold for the 1.1% factor. Leftover days that do not complete a whole month are dropped.

The survivor election

Electing a full survivor benefit reduces your own annuity by 10% and pays your survivor 50% of the annuity as it stood before that reduction. The partial election costs 5% and pays 25%. The reduction is applied last, after any age reduction.

What this does not model

Deliberately out of scope, because each would need inputs this form does not ask for:

• The FERS annuity supplement — payable to some retirees who go before 62, and subject to an earnings test.
• Special provisions for law enforcement officers, firefighters, and air traffic controllers, which use a different and more generous formula.
• CSRS and CSRS Offset, which are separate systems with their own formula.
• Cost-of-living adjustments, deposits and redeposits for unpaid service, part-time proration, and any court-ordered apportionment.
• Taxes and withholding, including FEHB and FEGLI premiums taken out of the monthly payment. Every figure here is gross.

Sources

• OPM CSRS/FERS Handbook, Chapter 50 — Computation of Annuity Under the General Formula (PDF) — the formula, the 1.1% factor, and the order in which reductions apply.
• OPM CSRS/FERS Handbook, Chapter 51 — Creditable Service (PDF) — the 2,087-hour sick leave conversion and its exclusion from eligibility.
• OPM — FERS Retirement Eligibility — the age and service combinations, and the MRA table by year of birth.
• 5 U.S.C. § 8415 — the statute the handbook restates, including the MRA+10 reduction at subsection (f).

Last reviewed: August 2026