FERS vs BRS: Which Retirement System Are You Under?

One of the most common questions veterans entering federal civilian service ask is deceptively simple: which retirement system am I under? The answer depends on when you served, when you were hired as a civilian, and in some cases, whether you made an election you may have forgotten about. Getting this wrong — or just not knowing — can mean years of miscalculating your expected retirement income.

The Two Systems in Play

Federal civilian employees hired after January 1, 1984 fall under the Federal Employees Retirement System, known as FERS. Before that date, employees were covered by the Civil Service Retirement System, or CSRS. CSRS is largely frozen to new entrants — if you're reading this and you're under 50, there's almost no scenario where you're in CSRS. FERS is your system.

For military members, the parallel question is whether you're under the legacy High-3 retirement system or the Blended Retirement System (BRS). Anyone who entered service before January 1, 2018 was grandfathered into the legacy system unless they opted into BRS during the 2018 opt-in window. Anyone who entered on or after January 1, 2018 is automatically under BRS.

What FERS Actually Pays You

FERS is a three-legged stool: your pension (annuity), your TSP balance, and Social Security. Your pension is calculated as 1% of your high-3 average salary multiplied by your years of creditable service. If you retire at age 62 or later with at least 20 years of service, that multiplier bumps to 1.1%. So a GS-12 with a $90,000 high-3 average and 25 years of service would receive approximately $22,500 per year — before any survivor benefit reductions.

That pension alone won't fund a retirement. FERS was designed with the assumption that TSP contributions would carry much of the load.

What BRS Actually Pays You

The legacy military retirement system paid 50% of your base pay after 20 years, scaling up to 75% at 30 years. Nothing if you left before 20. BRS changed the math significantly. The multiplier dropped to 2% per year (down from 2.5%), so 20 years now yields 40% of base pay instead of 50%. In exchange, service members under BRS receive automatic and matching TSP contributions starting from day one, plus a mid-career Continuation Pay bonus.

For members who serve a full career, BRS pays less in pension. For members who separate before 20 years, BRS pays something where legacy paid nothing.

The Veteran Who Transitions to Federal Civilian Service

If you served under the legacy military retirement system and then became a federal civilian employee, you're now under FERS — and your military time may count toward your FERS retirement if you make a deposit to OPM. That deposit equals 3% of your military basic pay for each year of service, plus interest. It's often worth doing, especially for longer periods of service, because each credited year adds another 1% multiplier to your FERS pension.

If you're receiving military retirement pay, you generally cannot also receive a FERS pension credit for the same years without waiving your military retirement — unless you're a disability retiree. This is a decision worth running through a benefits counselor before you make it.

How to Verify Which System You're Under

For federal civilians: log into Employee Express or check your most recent SF-50 (Notification of Personnel Action). Box 30 will list your retirement plan code. Code K or M indicates FERS. Code 1 or 6 indicates CSRS.

For military members: if you entered service before 2018 and aren't sure whether you opted into BRS, check your MyPay account or contact your unit's finance office. The opt-in window closed December 31, 2018, so if you didn't elect BRS, you stayed in the legacy system.

Why This Matters Before You Can Calculate Anything Else

Every retirement projection — whether you're using a FERS calculator, estimating your TSP target, or modeling when you can afford to retire — starts with knowing which system governs your pension. Getting that foundation right is step one. Everything else builds from there.

Not sure how your military service years interact with your FERS calculation? Check our FERS deposit guide to see whether buying back your time makes financial sense.