The Three Parts of Your Federal Retirement Income

Updated June 2026 · Educational only — not financial, tax, or legal advice

FERS was built as a "three-legged stool." Your retirement income doesn't come from one source — it comes from three, each with its own rules, timing, and tax treatment. Understanding how the three legs fit together is the difference between a stack of separate benefits and an actual retirement plan.

Leg 1 — Your FERS pension

The foundation: a guaranteed monthly annuity for life, computed from your high-3 and your years of service, and adjusted for inflation with cost-of-living increases. It's the one leg that's fully defined for you and never runs out. See how your FERS pension is calculated.

Leg 2 — Social Security (and the bridge before 62)

Unlike the old CSRS system, FERS employees pay into Social Security and earn a normal benefit. But there's a timing wrinkle: Social Security isn't available until 62 at the earliest, while many feds retire well before that. That's what the FERS Annuity Supplement is for — it bridges the gap from retirement to 62, approximating your Social Security earned during federal service. Then at 62 the supplement ends and the real Social Security claiming decision begins. See Social Security for federal employees.

Leg 3 — Your TSP

The flexible leg — and often the largest. Your Thrift Savings Plan is the part you actively control: how much to draw, from which balance (traditional or Roth), and when. That flexibility is exactly why it's where the most planning value — and the most avoidable mistakes — live.

Why integration is the hard part

Each leg is manageable on its own. The challenge is that they interact:

• The supplement ends at 62 — but should you claim Social Security then, or delay for a larger benefit and bridge the gap from your TSP?
• Every dollar from your traditional TSP is taxable income that stacks on your pension and Social Security — and can raise your tax bracket and Medicare premiums.
• The low-income years between retirement and age 73 are often the best window for Roth conversions — before required minimum distributions force the issue.

Optimizing one leg in isolation can quietly cost you on another. The real work — and where a plan earns its keep — is sequencing all three together. See building your retirement paycheck.