Roth vs. Traditional TSP: Which Should You Choose?
Updated June 2026 · ~5 min read
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The Thrift Savings Plan (TSP) lets you contribute in two flavors: Traditional (pre-tax) and Roth (after-tax). Both are excellent; the right choice mostly comes down to one question: will your tax rate be higher now, or in retirement?
How each is taxed
| Traditional TSP | Roth TSP |
|---|
| When you contribute | Pre-tax — lowers your taxable income now | After-tax — no break today |
| While invested | Grows tax-deferred | Grows tax-free |
| When you withdraw | Taxed as ordinary income | Qualified withdrawals are tax-free |
The deciding question: your tax rate, now vs. later
- Roth wins if you expect your tax rate to be higher in retirement than it is today. You pay tax now at a low rate and never again.
- Traditional wins if you expect your tax rate to be lower in retirement. You skip tax now at a high rate and pay later at a lower one.
- If the two rates are equal, the after-tax result is roughly the same.
Many junior service members are in low tax brackets now and may earn more (and face higher rates) later — which often favors Roth early in a career.
The combat-zone superpower: Pay earned in a tax-exempt combat zone is already untaxed. Contribute that pay to the Roth TSP and the money is never taxed — not going in, not growing, and not coming out. It's one of the best deals in the entire tax code.
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Important: the government match is always Traditional
No matter which flavor you choose for your own contributions, all government automatic and matching contributions go into your Traditional balance. So most BRS members end up with both balances — Roth from their own contributions and Traditional from the match.
A few practical notes
- The annual contribution limit ($24,500 in 2026) is shared across Roth and Traditional combined.
- You can split your contribution between Roth and Traditional, and change the mix anytime.
- Qualified Roth withdrawals require being age 59½ and the account being open at least 5 years.
- Not sure? Many people hedge by contributing to both, creating tax flexibility in retirement.
Compare Roth vs. Traditional with your numbers →
Related reading: BRS vs. High-3 explained · How the TSP 5% match works
This article is for general education only and is not financial or tax advice. CalculateTSP is independent and not affiliated with, endorsed by, or sponsored by the U.S. Department of Defense, DFAS, or the Federal Retirement Thrift Investment Board. Consult a tax professional for your situation.