An IRA contribution optimizer helps you decide whether to put your retirement savings into a Traditional IRA (pre-tax deduction, taxed on withdrawal) or a Roth IRA (after-tax contribution, tax-free withdrawal). The right choice depends entirely on your current tax bracket versus your expected retirement tax rate — and this calculator shows you the exact dollar difference.
Your Retirement Details
2026 limit: $7,000 (under 50) or $8,000 (age 50+)
Historical stock market average: ~7% real return
Roth IRA
Pay tax now, withdraw tax-free
Traditional IRA
Deduct now, pay tax on withdrawal
Year-by-Year Growth (Every 5 Years)
| Year | Age | Roth Value | Trad. After-Tax |
|---|
Decision Matrix
Choose Roth if: You expect your retirement tax rate to be higher than today's rate, or if you are in a low bracket now (10-22%) and expect higher income later.
Choose Traditional if: You are in a high bracket now (32-37%) and expect lower income in retirement. The upfront deduction is worth more than tax-free growth.
When they tie: At the break-even tax rate shown above, both accounts produce identical after-tax outcomes.
How to Use the IRA Contribution Optimizer
The IRA contribution optimizer takes your personal financial situation — your age, tax bracket, and expected retirement income — and calculates which account type (Traditional or Roth) will leave you with more money after taxes at retirement.
Step 1: Enter Your Ages and Contribution
Start with your current age and target retirement age. The number of years between them is your investment horizon — the longer it is, the more compounding works in your favor for either account type. Enter your planned annual contribution up to the 2026 IRA limit ($7,000 under 50, $8,000 age 50+).
Step 2: Set Tax Rates
Your current marginal tax rate determines what a Traditional IRA deduction is worth today. Your expected retirement tax rate determines what you will owe on Traditional withdrawals. The wider the gap between these two rates, the stronger the case for one option over the other.
Step 3: Review the Break-Even Rate
The break-even tax rate is the retirement tax rate at which both accounts produce identical outcomes. If your expected retirement rate is above the break-even, Roth wins. Below it, Traditional wins. This single number summarizes the entire comparison.
How the Math Works
Roth IRA: You pay income tax on the contribution now, invest the after-tax amount, and the entire balance grows tax-free. No taxes on withdrawal in retirement. Traditional IRA: The full contribution grows pre-tax, but you owe income tax on every dollar withdrawn in retirement. The key insight: when tax rates are equal, both accounts produce identical outcomes — the tax timing does not matter. Only a tax rate difference creates a winner.
2026 IRA Contribution Limits
The 2026 IRA contribution limit is $7,000 per person (combined across all Traditional and Roth IRAs). If you are age 50 or older, you can contribute an additional $1,000 catch-up contribution for a total of $8,000. Note: Roth IRA contributions phase out at higher income levels ($150,000+ for singles, $236,000+ for married couples filing jointly in 2026).
FAQ
Is this IRA contribution optimizer free?
Yes, completely free with no signup required. All calculations run locally in your browser — your income, tax rates, and contribution amounts are never sent to any server.
Is my financial data safe?
Absolutely. Everything runs in your browser. No data is transmitted or stored anywhere. You can disconnect from the internet after loading the page and all calculations continue to work.
What is the 2026 IRA contribution limit?
For 2026, the IRA contribution limit is $7,000 per year (up to $8,000 if you are age 50 or older). This applies to both Traditional and Roth IRAs combined. Income limits apply for Roth IRA eligibility and Traditional IRA deductibility.
When is a Roth IRA better than Traditional?
Roth wins when your expected tax rate in retirement is higher than your current tax rate. You pay tax now at the lower rate and enjoy tax-free withdrawals later. This is most beneficial for younger earners in lower brackets who expect income to rise, or anyone expecting high retirement income from Social Security, RMDs, or other sources.
When is Traditional IRA better than Roth?
Traditional IRA wins when your current tax rate is higher than your expected retirement rate. The upfront tax deduction is worth more than the future tax-free growth. This often benefits high earners in the 32-37% bracket who plan to withdraw in the 22-24% range in retirement.
What is the IRA break-even tax rate?
The break-even tax rate is the retirement tax rate at which Roth and Traditional produce identical after-tax outcomes. If your actual retirement rate is above the break-even, Roth wins. Below the break-even, Traditional wins. This calculator finds your exact break-even rate.
Can I contribute to both Traditional and Roth IRA?
Yes, but your combined contribution to all IRAs cannot exceed the annual limit ($7,000 in 2026, $8,000 if 50+). You can split between account types but total contributions are capped. For example, $3,500 to Traditional and $3,500 to Roth is allowed.
What annual return rate should I use?
A commonly used long-term average for a diversified stock portfolio is 7% per year in real terms. Conservative planners often use 5-6%. The return assumption matters because higher returns amplify the Roth advantage — tax-free growth compounds faster over time.