The Traditional-vs-Roth question stops a lot of federal employees in their tracks, but the underlying choice is simpler than it sounds. Your TSP can hold two kinds of money, and they're identical in every way but one: when you pay tax on it. Get that one decision roughly right and it can be worth a meaningful amount over a career — but there's no version where you "lose" by saving.
The core difference
Both options take money from your paycheck into the same funds. The fork is the tax timing.
Traditional TSP — pay later
Contributions come out before tax, so they lower your taxable income today. The money grows untaxed, and then your withdrawals in retirement — contributions and growth alike — are taxed as ordinary income. You're deferring the tax bill to your future self.
Roth TSP — pay now
Contributions come out after tax, so there's no deduction today. In exchange, qualified withdrawals in retirement — including every dollar of growth — come out completely tax-free. You're settling the tax bill now and never paying it again on that money.
| Traditional | Roth | |
|---|---|---|
| Tax on contributions | Pre-tax (deducted now) | After-tax (no deduction) |
| Tax on withdrawals | Taxed as ordinary income | Tax-free (if qualified) |
| RMDs for you | Yes (age 73 / 75) | None |
| Best if your future bracket is… | Lower than today | Same or higher |
| Agency match goes to… | Always Traditional | Always Traditional |
The deciding question: your tax bracket, now vs. later
Strip away the jargon and the whole decision is a bet on your future tax rate:
- Traditional wins if you expect to be in a lower bracket in retirement than you are now — you skip the tax at today's high rate and pay it later at a lower one.
- Roth wins if you expect your bracket to be the same or higher — you lock in today's rate on the seed and let all the growth escape tax entirely.
Here's the federal wrinkle most calculators miss: a FERS pension plus Social Security is guaranteed taxable income that lands every month of retirement. Many federal retirees discover their bracket doesn't drop nearly as much as a private-sector retiree's would — and sometimes doesn't drop at all. That reality nudges a lot of feds toward Roth, or toward holding both.
The match always goes to Traditional
This one surprises people: no matter how you direct your own contributions, your agency's automatic 1% and matching contributions always land in your Traditional balance. So even a 100%-Roth contributor steadily builds a Traditional bucket from the match — and will owe tax on that portion someday. It's not a problem; it's just a reason almost everyone ends up with some of both, whether they planned to or not.
Pro Tip
You don't have to pick just one. Splitting your contributions between Traditional and Roth gives you tax diversification — two pools to draw from in retirement so you can manage your bracket year to year, pulling from Traditional up to a tax threshold and Roth beyond it. For many federal employees who can't confidently predict their future rate, a deliberate mix is the most defensible answer.
Roth's quiet advantages beyond taxes
Even setting the bracket math aside, the Roth balance carries a few structural perks:
- No RMDs for you. As of 2024, Roth TSP is no longer subject to required minimum distributions (RMDs) during your lifetime. Traditional balances must start RMDs at age 73 (or 75 if you were born in 1960 or later), whether you need the money or not.
- Tax-free to heirs. Money your beneficiaries inherit from a Roth generally comes to them tax-free, which makes it a cleaner legacy asset.
- Bracket control in retirement. Tax-free Roth withdrawals don't add to your taxable income, so they're a lever for staying under thresholds that affect Medicare premiums and Social Security taxation.
One caveat on the "tax-free" part: Roth withdrawals are only fully tax-free if they're qualified — generally, the account has been open at least five years and you're 59½ or older. Pull earnings early and they can be taxed.
What changed for 2026
Two SECURE 2.0 Act provisions reshape the Roth picture this year:
Mandatory Roth catch-up for higher earners
Starting in 2026, if your prior-year wages from your federal job topped $150,000, any catch-up contributions you make (the dollars above the $24,500 limit) must go into Roth, not Traditional. Your regular contributions are still your choice — only the catch-up portion is affected. It doesn't change how much you can save, just the tax treatment, so if you were counting on that pre-tax deduction, plan around it.
In-plan Roth conversions
The TSP now lets you convert money from your Traditional balance to Roth inside the plan, without rolling it out to an Individual Retirement Account (IRA) first. It's a useful tool for gradually shifting money to the tax-free side — but a conversion is a taxable event in the year you do it, so the converted amount is added to your income that year.
Watch Out
A Roth conversion can push you into a higher bracket and means a tax bill you'll owe from other cash — never from the converted money itself. Done gradually and deliberately (often in lower-income years between retirement and when RMDs or Social Security start), conversions can smooth a lifetime of taxes. Done carelessly, they create an avoidable spike. This is the kind of move worth running by a tax professional first.
2026 contribution limits
- $24,500 — the standard elective deferral limit (this is the combined cap across Traditional and Roth, not each).
- +$8,000 catch-up if you're 50–59 or 64+.
- +$11,250 super catch-up if you're 60–63 during the year.
And the universal reminder: contribute at least 5% of your pay — Traditional or Roth, it doesn't matter for this — to capture the full agency match. That's the one rule no one should break.
So which should you choose?
There's no single right answer, and anyone who gives you one without knowing your tax situation is guessing. The honest framework: if you're early in your career or in a lower bracket now, Roth's tax-free growth has decades to compound. If you're in your peak earning years and a high bracket, the Traditional deduction is valuable today. And if you genuinely can't tell — which is most people — a deliberate split hedges the bet. Whatever you choose, the worst option is contributing less than 5% and leaving the match on the table.
Your TSP is one leg of the three-legged stool, alongside your FERS pension and Social Security — and the tax decision is best made looking at all three together.
Frequently asked questions
What's the difference between Traditional and Roth TSP?
Traditional is pre-tax — it lowers your taxable income now, and withdrawals are taxed later. Roth is after-tax — no deduction now, but qualified withdrawals, including growth, are tax-free. The question is whether you'd rather pay tax now or later.
Does the agency match go to Traditional or Roth?
Always Traditional, even if you contribute only to Roth. A Roth-only contributor still builds a Traditional balance from the match and will owe tax on that portion at withdrawal.
Does Roth TSP have RMDs?
No — as of 2024, Roth TSP is not subject to required minimum distributions during your lifetime. Traditional TSP still has RMDs, beginning at age 73 (or 75 if born in 1960 or later).
What are the 2026 mandatory Roth catch-up rules?
If your prior-year federal wages exceeded $150,000, your catch-up contributions must go into Roth in 2026. Your regular contributions up to $24,500 are still your choice — only the catch-up dollars are affected.
Should I choose Traditional or Roth?
It depends on your tax bracket now versus in retirement. Traditional favors a lower future bracket; Roth favors a same-or-higher one. Because a FERS pension plus Social Security often keeps feds in a high bracket, many split contributions for tax diversification. There's no single right answer.