Plug in your current and expected retirement tax rates, contribution amount, and years to grow — and the calculator tells you which IRA actually wins with your specific numbers.
Every personal finance thread eventually splits into the same two camps: "Roth, always, tax-free growth is king" versus "Traditional, obviously, take the deduction now." Both camps are confidently wrong about half the time, because the only thing that decides it is the one variable nobody in the thread knows — the gap between your tax bracket today and your tax bracket the year you start pulling the money out. This calculator takes your gross income, your current bracket, your expected retirement bracket, your contribution, and your years to grow, runs both paths through a projected return, and hands you a real after-tax dollar figure for each.
The output is not a vague recommendation. It shows Roth Net — the after-tax value at retirement — alongside Traditional Net, declares a winner, and quantifies the advantage in dollars. If retirement is 25 years away and the two accounts are within $8,000 of each other, that tells you something different than if the gap is $60,000. Knowing which side it lands on and by how much is the whole point.
Why the tax bracket spread is the only number that matters
A Roth contribution costs you tax money today but nothing at withdrawal. A Traditional contribution saves you tax today and costs you later. The bet you are making is whether your tax rate will be higher now or in retirement. If you earn $85,000 today in the 22% bracket and expect to draw $40,000 annually in retirement from a lower bracket, Traditional usually wins. If you are a 28-year-old earning $60,000 and expect a long career of income growth, Roth is often the better call.
The tool makes that comparison explicit. You enter Current Tax Bracket (%) and Expected Retirement Tax Bracket (%), and the model prices each path accordingly. A 10-point spread one way or the other can move the winner's advantage into five figures over 25 years of compounding. The numbers are not fuzzy projections — they are arithmetic, and you can see them shift in real time as you change either rate.
How the compounding math plays out over time
Both IRA types grow tax-deferred inside the account, but the starting point differs. With a Roth, you contribute after-tax dollars, so a $6,500 contribution from a $8,333 pre-tax pool if you are in the 22% bracket. With Traditional, you contribute the full $6,500 pre-tax, but every dollar you pull in retirement gets taxed. The calculator's year-by-year projection uses your Expected Return (%) to model both balances side by side so you can see where the lines cross — or whether they ever do.
Over 30 years at a 7% return, the difference between a Roth advantage and a Traditional advantage often hinges on the retirement tax bracket assumption. If your assumed retirement bracket is 12%, Traditional wins in almost every scenario at today's contribution limits. If it is 24%, Roth tends to pull ahead. The projection chart makes this visible instead of leaving it to a rule of thumb.
The Roth conversion question: when to flip
The tool includes a conversion analysis — whether moving existing Traditional IRA funds into a Roth makes sense. The core of that math is: can you afford to pay the conversion taxes now, and will you be in a lower bracket before required minimum distributions kick in at age 73? A common window for conversions is between retirement and age 73 when earned income drops but RMDs have not started yet.
The conversion section does not replace a CPA, but it surfaces the question in concrete terms. If the math on your numbers shows a meaningful Roth advantage and you have substantial Traditional IRA funds, it is a conversation worth having with a tax professional before the next bracket adjustment.
Annual contribution limits and catch-up rules
The 2026 IRA contribution limit is $7,000 per year for individuals under 50, and $8,000 for those 50 and older with the catch-up provision. Neither Roth nor Traditional is exempt from this aggregate cap — if you contribute $5,000 to a Roth, you can only add $2,000 to a Traditional in the same year. Enter your actual planned annual contribution in the Annual IRA Contribution field; if you are maxing out, use $7,000 or $8,000.
Income limits for Roth direct contributions phase out starting at $146,000 for single filers and $230,000 for married filing jointly in 2026. If your income is above those thresholds, a backdoor Roth strategy may apply — the tool's standard comparison still shows you the theoretical advantage of each path so you know what the tax work is worth.
Reading the winner output and acting on it
When you see Winner and the Advantage in dollars at the top of the results panel, the practical question is whether the margin is material enough to dictate strategy. If Traditional wins by $12,000 over 30 years, that is real money but not a reason to ignore liquidity. Roth accounts allow penalty-free withdrawal of contributions at any age, which is worth something if you want flexibility. Traditional accounts reduce taxable income today, which matters if you are close to a bracket boundary.
Use the tool to test your actual scenario, not a hypothetical. A 40-year-old in the 24% bracket expecting a 15% retirement rate will see a very different result than a 30-year-old in the 12% bracket expecting a 22% retirement rate. The calculator does not know your situation — you do. Feed it your real numbers and let it do the arithmetic.
How to use it
- Enter your Annual Income (gross) and Current Tax Bracket (%) — check your most recent return if unsure.
- Set Expected Retirement Tax Bracket (%) based on your anticipated withdrawal amount and filing status in retirement.
- Enter your planned Annual IRA Contribution and Years Until Retirement.
- Set Expected Return (%) — a 6–7% figure is a reasonable long-term assumption for a diversified portfolio.
- Read Winner, Roth Net, Traditional Net, and Advantage at the top, then check the Year-by-Year Projection to see how the gap evolves over time.
Who it's for
- Early-career earner in a low bracket — A 27-year-old earning $52,000 in the 12% bracket expects career advancement to push retirement income to the 22% range. The calculator confirms Roth wins by roughly $38,000 over 33 years at 7% return — paying the lower tax now saves heavily later.
- Mid-career professional near peak earnings — A 45-year-old in the 32% bracket with a $200,000 income plans to retire on $80,000 annually in the 22% bracket. Traditional IRA wins here — deferring at 32% and paying at 22% creates a meaningful advantage that compounds over 20 years.
- Pre-retiree weighing a Roth conversion window — A 62-year-old with $350,000 in Traditional IRA funds retires early with three years of low income before Social Security kicks in. The conversion analysis highlights a window to convert $50,000 per year at 12%, potentially saving tens of thousands versus waiting for RMDs at a higher bracket.
- Couple doing side-by-side planning — Spouses with different incomes run separate scenarios — one is in the 22% bracket, the other in the 12% bracket. The tool quickly shows that the lower-income spouse benefits more from Roth while the higher earner leans Traditional, informing a split contribution strategy.
Key terms
- Roth IRA
- An individual retirement account funded with after-tax dollars. Withdrawals in retirement, including growth, are tax-free, provided the account has been open at least five years and you are 59.5 or older.
- Traditional IRA
- A retirement account funded with pre-tax dollars (if you meet deductibility requirements). Contributions reduce your taxable income today; withdrawals in retirement are taxed as ordinary income.
- Tax bracket
- The marginal rate applied to each additional dollar of income within a given range. A 22% bracket means the last dollars earned before the next threshold are taxed at 22%, not that all income is taxed at 22%.
- Roth conversion
- Moving funds from a Traditional IRA to a Roth IRA. You pay income tax on the converted amount in the year of conversion, then all future growth and qualified withdrawals are tax-free.
- Required Minimum Distribution (RMD)
- The minimum amount the IRS requires you to withdraw annually from Traditional IRAs starting at age 73. Roth IRAs have no RMDs during the owner's lifetime.
Frequently asked questions
What if I expect my tax rate to stay the same in retirement?
If current and retirement brackets are identical, Traditional still has a slight edge because you get more money working in the account over time — the pre-tax contribution is larger than the after-tax equivalent. The tool models this exactly; run it with equal brackets and you will see Traditional win by a small margin.
Does the calculator account for required minimum distributions?
The model uses your years until retirement as the projection horizon and shows the after-tax value at that point. RMDs, which begin at age 73 for Traditional IRAs, are not modeled year-by-year, but the retirement tax bracket assumption is where that impact shows up — if you expect RMDs to push you into a higher bracket, raise your expected retirement tax rate accordingly.
How should I estimate my retirement tax bracket?
Add up your expected annual income sources in retirement: Social Security (which is 50–85% taxable depending on total income), Traditional IRA or 401k withdrawals, pension if any, and investment income. Look up which federal bracket that total lands in. Most middle-income retirees end up in the 12% or 22% bracket. If Social Security plus RMDs push past $100,000 annually, the 22–24% range is common.
Can I contribute to both a Roth and Traditional IRA in the same year?
Yes, but the combined total must stay within the annual limit — $7,000 if under 50, $8,000 with the catch-up. Some people split contributions to hedge their tax bet. The calculator compares all-in one direction; run it for each option and compare the net advantage to decide how to split.
Is this the same calculation a financial advisor would run?
The core tax-bracket comparison is identical to what a fee-only advisor uses. Advisors also factor in estate planning, Social Security timing, and state taxes, which this tool does not model. For a full plan those details matter, but for the core Roth versus Traditional decision, this calculation gives you the right directional answer.