Side-by-side comparison with growth curves — drag sliders to see which wins for you.
Traditional 401(k) contributions are pre-tax (lower taxes now), Roth IRA contributions are post-tax (tax-free withdrawals later). Enter your income and contribution to see which wins over 30 years.
FreeToolHub 401k vs Roth IRA Calculator is a free browser-based tool that compares retirement account outcomes over 30 years, no signup.
2026 401(k) contribution limit: $23,500 ($31,000 if age 50+). Roth contributions are post-tax; Traditional are pre-tax. Investment returns assumed at 7% nominal. This is for estimation only — consult a financial advisor.
About this tool
Which retirement account makes you richer in 30 years? Free side-by-side projection.
What Is the 401(k) vs Roth IRA Comparison Tool?
The 401(k) vs Roth IRA comparison tool is a free browser-based calculator that projects the after-tax value of pre-tax (traditional 401k) versus post-tax (Roth IRA) contributions over your working career. Unlike generic retirement calculators that only show future balances, this tool models your actual marginal tax bracket today versus your expected bracket in retirement — the single most important variable in the 401k vs Roth decision. It accounts for 2026 IRS contribution limits ($23,500 for 401k, $7,000 for Roth IRA), employer match vesting schedules, and compound growth over customizable time horizons. All calculations run locally in your browser; no financial data is transmitted to any server.
Who Should Use This Tool?
This tool is built for employees offered both a traditional 401(k) and a Roth IRA (or Roth 401k) who want to understand which option maximizes after-tax retirement wealth. Young professionals in lower tax brackets often benefit from Roth contributions since they pay taxes now at a lower rate and withdraw tax-free later. Higher earners in peak earning years may prefer traditional 401(k) contributions for the immediate tax deduction. Financial planners use this calculator to illustrate the tax diversification strategy — splitting contributions between both account types — to clients at any income level. Freelancers comparing a Solo 401(k) against a Roth IRA for self-employed retirement planning also find the side-by-side projections useful.
How to Use the 401(k) vs Roth IRA Calculator
Enter your current age, planned retirement age, annual salary, and expected annual raise into the input fields. Specify your current federal and state marginal tax rates, then estimate your retirement tax bracket based on expected income in retirement. The tool instantly computes projected after-tax balances for both a traditional 401(k) and a Roth IRA using 2026 contribution limits and historical S&P 500 average returns (adjusted for inflation). The results panel shows year-by-year growth, total taxes paid over your career under each scenario, and the breakeven retirement bracket where both options produce identical after-tax wealth. Adjust any input to see results update in real time.
Frequently asked
How does it project 401(k) vs Roth IRA growth?
It compounds contributions over 10, 20, or 30 years using your marginal tax rate, expected return (default 7% inflation-adjusted), and employer match. The key difference: a 401(k) defers tax on withdrawal while a Roth taxes contributions now but grows tax-free. The tool shows which leaves more after-tax dollars at retirement.
At what tax bracket does a Roth IRA usually win?
If your current marginal rate is below 22%, the Roth typically wins because you pay tax now at a low rate and withdraw tax-free later. Above the 24% bracket, a traditional 401(k) often yields more after-tax income, especially if you expect a lower rate in retirement.
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