Federal Retirement Income Tax: How Taxes Hit Your Income and How to Lower Them

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Taxes on federal retirement income include the federal and state taxes that may apply to a retired federal employee's main income streams: FERS pension, TSP withdrawals, and Social Security benefits. Most of this income is taxed as ordinary income. Each source follows its own rules, and coordinating them is where retirees may reduce or increase their lifetime tax bill significantly.

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This guide explains how each stream is taxed in 2026 and the specific moves that may lower your bill. Federal Pension Advisors, a retirement planning firm specializing in federal employee benefits, prepared this overview to help you plan before the tax surprises arrive.

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One of the most expensive mistakes federal retirees make is assuming retirement income is taxed lightly. It is not.

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With a FERS pension, TSP withdrawals, and Social Security stacking on top of one another, most federal retirees land in the same tax brackets they occupied while working. Some land higher.

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How Your FERS Pension Is Taxed

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Your FERS pension is taxed as ordinary income at the federal level, with only a small portion treated as a tax-free return of your own contributions. FERS, the Federal Employees Retirement System, pays a monthly annuity through OPM, the U.S. Office of Personnel Management. Because you contributed after-tax dollars during your career, a small portion of each payment comes back to you tax-free.

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According to IRS Publication 721, the Tax Guide to U.S. Civil Service Retirement Benefits, the taxable portion of a FERS annuity includes the government's contributions plus all investment earnings. The nontaxable portion represents the recovery of your already-taxed contributions. OPM calculates the tax-free amount for you and reports the taxable figure on your annual Form 1099-R, so you don't have to run the math yourself.

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The tax-free slice is genuinely small. One illustration from Fed Pilot estimates that a federal employee who contributed at the 0.8% rate over a 30-year career at an average salary of $80,000 might recover only $65 to $80 per month tax-free.

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The overwhelming majority of every FERS annuity payment is taxable.

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OPM automatically withholds federal income tax from your annuity based on the Form W-4P you submitted at retirement. If you haven't updated that form in years, your withholding may no longer match your actual income. That mismatch is a common source of tax bills at filing time.

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How TSP Withdrawals Are Taxed

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How your TSP withdrawal is taxed depends entirely on whether the money sits in a Traditional or a Roth balance. The TSP (Thrift Savings Plan), is the federal government's tax-advantaged retirement savings program, and it's taxed separately from your FERS annuity.

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Withdrawals from your Traditional TSP are fully taxable as ordinary income, because both your contributions and earnings went in pre-tax. Every dollar you pull stacks on top of your pension and Social Security in the year you receive it.

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According to the TSP's tax booklet (TSPBK26), many lump-sum and partial withdrawals carry 20% federal withholding. The exact rule depends on the payment type, and your actual liability is reconciled at filing.

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Qualified Roth TSP withdrawals, by contrast, are generally federal income tax-free when the 5-year rule and age 59 1⁄2 or another qualifying condition are met. This is the central advantage of having funded the Roth TSP during your career.

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A major 2026 change expands your options here. According to FedWeek's 2026 TSP coverage, federal employees can now contribute up to $24,500 to the TSP, with an additional $8,000 catch-up for those age 50 and older.

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Just as important, in-plan Roth conversions are now available directly inside the TSP. You can convert Traditional dollars to Roth in controlled amounts, but the converted amount is generally taxable in the year of conversion.

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Use our TSP calculator to model different withdrawal scenarios.

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How Social Security Is Taxed in Retirement

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Up to 85% of your Social Security benefits can be subject to federal income tax, depending on your "combined income." The Social Security Administration defines combined income as your adjusted gross income, plus any tax-exempt interest, plus half of your Social Security benefits.

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Here's how the thresholds work for single filers, according to the Social Security Administration. With combined income between $25,000 and $34,000, up to 50% of benefits become taxable. Above $34,000, up to 85% become taxable.

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For married couples filing jointly, the 50% band runs from $32,000 to $44,000. Above $44,000, up to 85% is taxable.

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FedWeek emphasizes a hard reality for federal retirees. With a FERS pension plus TSP withdrawals plus Social Security, you will almost certainly exceed these thresholds, making up to 85% of your benefit taxable. The thresholds aren't indexed for inflation, so they pull more retirees into taxable-benefit territory over time.

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One bright spot: FedWeek notes that the 2025 federal tax law created an additional $6,000 deduction for each taxpayer age 65 and older for tax years 2025 through 2028. It phases out starting at $75,000 of modified adjusted gross income for single filers ($150,000 joint).

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The deduction doesn't change the Social Security taxation formula. It can lower your overall taxable income enough to reduce what you ultimately owe.

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The Side Effect Most Retirees Miss: IRMAA

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A large income year doesn't just raise your tax bill. It can raise your Medicare premiums two years later through IRMAA, the Income-Related Monthly Adjustment Amount. This surcharge is added to Medicare Part B and Part D premiums when your modified adjusted gross income exceeds a threshold.

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According to Kiplinger's 2026 Medicare analysis, the IRMAA surcharge in 2026 begins at $109,000 of modified adjusted gross income for single filers and $218,000 for joint filers, based on your tax return from two years prior. The structure is a cliff.

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As Federal Pension Advisors notes in its IRMAA guidance, crossing a threshold by a single dollar triggers the full surcharge for that tier. Total monthly Part B premiums in 2026 range from $202.90 up to $689.90 depending on income. A single oversized Traditional TSP withdrawal or Roth conversion can push you over a cliff and inflate your Medicare costs two years later.

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Comparison: How Each Income Source Is Taxed

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The table below summarizes the federal tax treatment of each major federal retirement income stream in 2026.

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Each row reflects 2026 federal rules. State treatment varies widely and is covered in the next section.

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State Taxes: One of Your Biggest Controllable Levers

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Where you live in retirement can matter as much as how you withdraw. State taxes on federal pensions range from full exemption to full taxation, and your residency at retirement, not where you worked, determines what you owe.

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According to the Tax Foundation's 2026 state tax overview, nine states levy no broad-based personal income tax: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming. Federal retirees who establish residency in any of them generally owe no state income tax on FERS annuity payments, TSP withdrawals, or Social Security benefits.

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A separate group of income-tax states specifically exempts federal civil-service pensions, and most states don't tax Social Security at all. If relocation is on your horizon, state tax treatment belongs in the decision.

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Seven Ways to Lower Your Federal Retirement Income Tax

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Use this ordered sequence to reduce your lifetime tax bill. Each step builds on the one before it.

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• Dial in your W-4P withholding. Submit an updated Form W-4P through OPM so your annuity withholding matches your real income, avoiding both penalties and oversized refunds that lock up cash.

• Coordinate which account you tap first. Traditional TSP withdrawals are fully taxable and qualified Roth withdrawals are tax-free, so blending the two lets you control your taxable income year by year.

• Use Roth conversions in low-income years. Convert Traditional TSP dollars to Roth during the gap between retirement and age 73, when your taxable income may be temporarily lower, locking in today's rates.

• Watch the IRMAA cliffs. Project your modified adjusted gross income two years forward before any large withdrawal or conversion, since crossing a threshold triggers the full Medicare surcharge.

• Time withdrawals across calendar years. Splitting a large TSP withdrawal and a Roth conversion across two tax years can keep both your bracket and your taxable Social Security share lower.

• Plan around the age-65 deduction. Coordinate income so you stay under the phase-out for the $6,000 senior deduction available through 2028.

• Factor in state residency. If you're mobile, evaluate the nine no-income-tax states and the states that exempt federal pensions before establishing retirement residency.

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A Real Planning Scenario

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Consider a FERS retiree we'll call Margaret, age 64, with a $48,000 annual pension, a $600,000 Traditional TSP balance, and Social Security beginning at 67. If Margaret waited until her required minimum distributions began at 73, her pension, Social Security, and TSP RMDs would stack together. That stack would likely push her modified adjusted gross income across the first IRMAA threshold of $109,000, triggering Medicare surcharges on top of higher income tax.

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By converting roughly $40,000 of Traditional TSP to Roth each year between 64 and 72, staying below the IRMAA cliff, she shrinks her future RMDs, builds a tax-free Roth balance, and smooths her taxable income across the decade. This is the kind of multi-year coordination Federal Pension Advisors, a retirement planning firm specializing in federal employee benefits, builds into a written withdrawal plan.

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Required Minimum Distributions and Your Tax Bill

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Required minimum distributions force taxable income out of your Traditional TSP whether you need the money or not. According to the TSP's 2026 plan-year guidance published on TSP.gov, RMDs begin at age 73 for many retirees, and the SECURE 2.0 Act raises the starting age to 75 for certain younger cohorts, depending on birth year.

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Miss an RMD and you trigger an IRS excise tax of 25% of the amount you should have withdrawn, reduced to 10% if corrected within a two-year window. Because RMDs land on top of your pension and Social Security, the years before 73 are your best window for proactive Roth conversions.

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Plan Before the Tax Bill Arrives

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Federal retirement income tax is often predictable, which means it can be planned for. The retirees who keep the most of their pension, TSP, and Social Security are the ones who map withdrawals, conversions, and residency years in advance rather than reacting each April.

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Federal Pension Advisors, a retirement planning firm specializing in federal employee benefits, helps federal employees build that coordinated, year-by-year plan. Schedule a federal retirement tax planning review with Federal Pension Advisors to see how these strategies apply to your own pension, TSP balance, and timeline.

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Frequently Asked Questions

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1. Is federal retirement income taxable?

Yes. Federal retirement income is generally taxable in 2026. Your FERS pension and Traditional TSP withdrawals are taxed as ordinary income, and up to 85% of Social Security benefits can be taxed. Only a small portion of your pension, representing your own after-tax contributions, is tax-free.

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2. How is my FERS pension taxed?

Your FERS pension is taxed as ordinary income at the federal level. According to IRS Publication 721, most of each annuity payment is taxable, while a small portion is a tax-free recovery of your after-tax contributions. OPM reports the taxable amount to you each year on Form 1099-R.

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3. Are TSP withdrawals taxed?

It depends on the account type. Traditional TSP withdrawals are fully taxable as ordinary income because contributions were pre-tax. Qualified Roth TSP withdrawals are generally federal income tax-free when you have held the account at least five years and are at least age 59½ or meet another qualifying condition, according to IRS rules.

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4. How much of my Social Security will be taxed?

Up to 85% of your Social Security benefits can be taxed. According to the Social Security Administration, for single filers with combined income above $34,000 (or $44,000 for joint filers), up to 85% becomes taxable. Most federal retirees exceed these thresholds.

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5. Can I lower the taxes on my federal retirement income?

Yes. The most effective levers are coordinating Traditional and Roth TSP withdrawals, completing Roth conversions in lower-income years before age 73, updating your W-4P withholding, timing withdrawals across calendar years, and choosing a tax-friendly state of residency.

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6. When do required minimum distributions start for the TSP?

According to TSP.gov 2026 guidance, required minimum distributions begin at age 73 for many retirees, rising to age 75 for certain younger cohorts under the SECURE 2.0 Act, depending on birth year. Missing one triggers an IRS excise tax of 25%, reduced to 10% if corrected within two years.

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Disclaimer

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This article is for informational and educational purposes only and does not constitute tax or financial advice. Federal benefit and tax rules change annually; verify all figures against OPM.gov, TSP.gov, IRS.gov, and SSA.gov for your plan year before making decisions.

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