Roth IRA vs. Traditional IRA Comparator

Model your future tax brackets to determine which retirement account leaves you with more after-tax wealth. Real-time comparison, 100% private.

Your Inputs
Contribution and Timeline
Tax Profile and Assumptions
The tax bracket your top dollar of income falls into today.
Your estimated average tax rate when you withdraw the funds.
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Enter your age and retirement age above to see your comparison.
Key Terms Explained
Marginal Tax Rate
The percentage of tax applied to your last (highest) dollar of income. Your overall tax bill is lower than this rate because earlier dollars are taxed at lower rates.
Effective Tax Rate
Your total federal tax paid divided by your total income - your actual average rate. Always lower than your marginal rate. This is the rate used to estimate Traditional IRA taxes at withdrawal.
Tax-Deferred
Money that grows without being taxed each year, but is taxed when withdrawn. Traditional IRA contributions and all growth inside the account are tax-deferred.
Tax-Free
Money that is never taxed on withdrawal. Qualified Roth IRA distributions (after age 59.5 and after a 5-year holding period) are completely tax-free, including all growth.
Required Minimum Distributions (RMDs)
Mandatory annual withdrawals the IRS forces from Traditional IRAs starting at age 73 (as of 2023). RMDs increase taxable income in retirement and can push you into higher brackets. Roth IRAs have no RMDs during the owner's lifetime.
Cost Basis
The original amount you paid into an investment, on which you have already paid income tax. Roth IRA contributions are your cost basis - you can withdraw them at any time without tax or penalty.
Future Value of an Annuity
The total value of a series of equal periodic payments after a set number of years of compound growth. This calculator uses this formula to project your IRA balance at retirement.
Tax Arbitrage
The strategy of paying taxes at a lower rate now (Roth) versus deferring to a potentially higher or lower rate later (Traditional). The optimal IRA choice is fundamentally a bet on your future tax rate relative to your current one.

The Complete Guide to Choosing Between a Roth and Traditional IRA

The choice between a Roth IRA and a Traditional IRA is one of the most consequential decisions in personal retirement planning - and one of the most misunderstood. Both accounts shelter your investments from annual capital gains taxes, but they differ in when the IRS takes its cut. Get this decision right and you can generate tens of thousands of dollars more in after-tax retirement income.

How to Use This Comparator

Enter your expected annual contribution, your current and retirement ages, and your expected investment return. Then enter your current marginal tax rate (the bracket your highest dollar of income falls into) and your estimated effective tax rate in retirement (your anticipated average rate across all income sources). The tool instantly calculates which account leaves you with more purchasing power after taxes.

The key insight: if your marginal rate today is higher than your effective rate in retirement, the Traditional IRA wins by letting you defer at a high rate and pay at a low one. If your expected retirement rate is equal to or higher than your current marginal rate, the Roth wins because you pay now at a lower rate and never owe again.

Why the Math Is Not Always Obvious

At first glance, it seems like the two accounts should produce identical results if tax rates stay the same. And mathematically, they do - if you invest the tax savings from a Traditional IRA deduction back into a taxable account. In practice, most people spend that refund rather than reinvesting it. The Roth forces a higher effective savings rate by requiring you to contribute after-tax dollars, which often tilts the real-world outcome in the Roth's favor even when the rate comparison is close.

The other major factor is account size. Large Traditional IRA balances can generate substantial RMDs starting at age 73, which can push retirees into unexpectedly high brackets - eroding the initial tax deduction benefit. Roth IRAs have no RMDs during the owner's lifetime, giving you more control over your taxable income in retirement.

The Case for the Traditional IRA

The Traditional IRA is optimal when you expect your tax rate to fall significantly in retirement. This is common for high earners in peak-income years who plan to live modestly in retirement, or for workers who expect tax rates broadly to decline. The immediate deduction is also valuable as a guaranteed return - a 22% deduction on $7,000 is $1,540 back in your pocket today, with certainty, regardless of market performance.

The Case for the Roth IRA

The Roth IRA is generally favored for younger workers in lower brackets who expect income to rise over their careers, for those who want flexibility (contributions can be withdrawn penalty-free at any time), and for those who believe tax rates will increase in the future. The complete absence of RMDs also makes the Roth an excellent vehicle for wealth transfer, since beneficiaries inherit a tax-free account.

A Practical Hedging Strategy

Since no one can predict future tax policy with certainty, many financial planners recommend splitting contributions between both account types across different years. Contribute to a Roth in years when your income (and thus your bracket) is lower, and shift toward a Traditional in high-income years. This tax diversification strategy smooths your exposure to rate uncertainty.

Frequently Asked Questions

How do I predict my retirement tax bracket? +
Start with your expected income sources in retirement: Social Security (up to 85% is taxable), Required Minimum Distributions from pre-tax accounts, pension payments, and any part-time work. Add these together and apply current tax brackets as a rough guide, knowing brackets will shift over time. Most retirees end up in the 12% to 22% federal bracket. If you expect significant RMDs from a large 401k or Traditional IRA, your effective rate could be higher than you think. The key insight is to estimate an effective (average) rate, not a marginal rate, since different dollars get taxed at different rates.
Why does the Traditional IRA give me a tax refund today? +
A Traditional IRA contribution is tax-deductible if you meet income and workplace retirement plan eligibility rules. This means the IRS lets you subtract your contribution from your taxable income for the year you make it. If you contribute $7,000 and you are in the 22% marginal bracket, your taxable income drops by $7,000, which typically results in about $1,540 less in federal taxes owed (or a larger refund). You are not avoiding the tax permanently - you are deferring it until you withdraw the money in retirement, at which point every dollar withdrawn is taxed as ordinary income.
Can I contribute to both a Roth and a Traditional IRA in the same year? +
Yes, but your combined contributions across all IRA accounts cannot exceed the annual IRS limit ($7,000 for 2025, $8,000 if age 50 or older). So you could put $3,500 in a Roth and $3,500 in a Traditional IRA, for example. However, your ability to deduct Traditional IRA contributions phases out at higher incomes if you or your spouse have a workplace retirement plan. Roth IRA contributions phase out at higher income levels entirely. Check current IRS Publication 590-A for the exact income thresholds.
What happens if taxes go up in the future? +
If tax rates rise significantly before you retire, the Roth IRA becomes more valuable because you already paid taxes at today's lower rates and all future growth and withdrawals are tax-free. The Traditional IRA exposes your entire balance - including decades of compounded growth - to whatever tax rates exist when you withdraw. This uncertainty is exactly why many financial planners recommend Roth accounts for younger workers who have a long runway and face possible rate increases. If you are unsure, splitting contributions between both account types is a common hedging strategy.
Estimates only - not financial or tax advice. This tool uses simplified assumptions: equal annual contributions, constant return rate, and a flat effective tax rate at withdrawal. It does not account for income phase-outs, state taxes, RMD impacts, the 5-year Roth rule, early withdrawal penalties, or future changes to tax law. Consult a qualified financial advisor or CPA before making IRA contribution decisions.