The choice between a Traditional IRA and a Roth IRA comes down to one question: do you expect your tax rate to be higher now or in retirement? The calculator above answers that mathematically by projecting the after-tax ending balance of both accounts under your inputs. Below we explain when each one wins, why the conventional wisdom of 'pick the lower-rate year' isn't always right, and how to use both at the same time.
The core math
A Roth contribution costs you the marginal tax rate today, but every dollar that grows inside the account is yours tax-free forever. A Traditional contribution gives you a deduction today (saving you the marginal rate now) but every dollar withdrawn in retirement is taxed as ordinary income.
If your current marginal rate equals your retirement rate, the two accounts produce identical after-tax balances. The Roth wins when your retirement rate is higher, the Traditional wins when your retirement rate is lower.
Why the Roth often wins even at lower retirement rates
Several factors tilt the comparison toward the Roth: the absence of RMDs (forced taxable withdrawals at 73), the favorable Social Security taxation rules (Roth distributions don't count toward provisional income), Medicare IRMAA premiums (Roth withdrawals don't trigger surcharges), and political risk (tax rates are historically low and many forecast they'll rise).
There's also a hidden contribution advantage. $7,000 into a Roth represents $7,000 of after-tax space, while $7,000 into a Traditional is partly tax-deferred space the IRS will eventually reclaim. On an after-tax basis, the Roth contribution is effectively larger — see our full Roth vs Traditional comparison for worked examples.
When the Traditional clearly wins
If you're in the 32–37% bracket today and reasonably expect to be in the 12% or 22% bracket in retirement (perhaps because you're a high earner planning a modest retirement lifestyle), a Traditional contribution captures a big upfront deduction that the Roth cannot match.
Self-employed people often pair a SEP IRA or Solo 401(k) (both pre-tax) with a Roth IRA, getting the best of both worlds in the same year.
Tax diversification: doing both
Many tax professionals recommend holding both Traditional and Roth balances by the time you retire. In retirement you can blend withdrawals: pull just enough Traditional to fill the standard deduction and 12% bracket each year, then top up income needs from the Roth tax-free.
This strategy can produce a sustained 0% effective tax rate on six-figure retirement spending in some scenarios — something neither account alone can achieve. The tax diversification strategy explains how to build this position.
Practical decision framework
Default to Roth if: you're early in your career, you expect your income to rise, you're in the 22% bracket or lower, you want maximum estate-planning flexibility, or you're hedging against future tax-rate increases.
Default to Traditional if: you're at a career income peak, you're confident your retirement income will be lower, you want the immediate tax deduction to free up cash flow, or you're in the 32%+ bracket.
When in doubt, split — direct half your annual IRA contribution to each, automatically building tax diversification over time. See Roth 401(k) vs Roth IRA if your employer offers both.
Frequently asked questions
Which is better, Traditional or Roth IRA?+
Roth wins if your retirement tax rate will be equal to or higher than today's. Traditional wins if you expect a meaningfully lower retirement rate. When uncertain, split between them.
Can I have both a Traditional and a Roth IRA?+
Yes. Many savers contribute to both. Combined annual contributions can't exceed the $7,000 / $8,000 limit.
Does the Traditional IRA have income limits?+
Not for contributions, but the tax deduction phases out if you (or your spouse) are covered by a workplace retirement plan. The Roth has income limits on the contribution itself.
What about employer matching?+
If your employer matches a 401(k), always capture the full match first — that's free money. After the match, the Traditional vs Roth question becomes the next decision.
How do RMDs affect this comparison?+
Traditional IRAs require RMDs starting at age 73, forcing taxable income whether you need it or not. Roth IRAs have no lifetime RMDs, which can extend tax-free compounding by decades.
