Roth 401(k) Calculator: Tax-Free Retirement Income
Contributions are after-tax, but qualified withdrawals — including all decades of growth — come out 100% tax free. Compare against Traditional 401(k) at your tax brackets.
Roth vs Traditional
How to Use This Roth 401(k) Calculator
Use this tool when the real question is tax timing: pay tax now with Roth or later with Traditional.
- Enter the same gross contribution for both options. That creates a fair apples-to-apples comparison because the pre-tax dollars leaving your paycheck are identical.
- Set current and retirement tax brackets. The gap between those two numbers is the core driver of whether Roth or Traditional wins.
- Review the after-tax winner, not just the pre-tax balance. Traditional may look larger before tax, but the comparison that matters is what you keep after retirement taxes.
How to Read the Results
Winner
This names the account type that leaves you with more after-tax retirement value under your assumptions.
Roth After-Tax Value
Qualified Roth withdrawals are tax-free, so this is already the spendable number.
Traditional After-Tax
This applies your retirement tax bracket to the traditional account balance.
Traditional Pre-Tax
This helps explain why Traditional can look bigger on paper even when Roth wins after taxes.
What to Do Next
How We Reviewed This Tool
Tool-Level Methodology
- Checked the Roth-versus-Traditional comparison around equal gross contribution amounts so the tax choice is evaluated on a like-for-like basis.
- Separated current-tax tradeoffs from retirement-tax outcomes to keep the decision framework readable for non-specialist users.
- Reviewed the tax-free withdrawal language against the site's Roth eligibility and age-based references before finalizing the copy.
Assumption Review
- The value comparison depends heavily on current versus retirement marginal tax rate assumptions; it is not a universal Roth-always-wins or Traditional-always-wins tool.
- Employer match treatment can differ by plan and is often contributed on a Traditional basis unless the plan permits otherwise.
- The model is designed for tax-planning comparison, not for projecting every distribution, conversion, or inheritance edge case.
Update Log
- Rechecked post-2024 Roth 401(k) no-RMD positioning so the supporting copy stays current.
- Aligned the page with the Roth-vs-Traditional guide and the flagship calculator so the tax choice can flow into broader retirement planning.
- Refreshed tax-bracket wording to match the current decision framework used across the site.
Roth 401(k) in One Sentence
You pay taxes on your contribution today, but neither the principal nor the growth will ever be taxed again — as long as you wait until age 59½ and have held the account at least 5 years.
When Roth 401(k) Wins
- Early-career workers. Low current bracket, high expected future bracket.
- Tax diversification. Hedge against future tax hikes by splitting 50/50 with Traditional.
- High earners who cannot use Roth IRA. Income phase-out stops Roth IRA, but Roth 401(k) has no income limit.
- Estate planning. Heirs inherit tax-free (subject to 10-year distribution rule).
When Traditional 401(k) Wins
- High earners near retirement. Expect lower bracket after retirement.
- Need for current-year deduction. Maxing Traditional at 37% marginal saves $9,065 in tax today.
- Very early retirement plans. Traditional + Roth IRA conversion ladder can be highly tax-efficient.
The Apples-to-Apples Test
The fair comparison is gross contribution (same dollars coming out of salary), not same net paycheck impact. Our calculator uses the gross approach: a $10,000 Roth contribution and $10,000 Traditional contribution are compared at their after-tax retirement values.
Frequently Asked Questions
What is a Roth 401(k)?
A Roth 401(k) is an employer-sponsored retirement account funded with after-tax contributions. Qualified withdrawals (age 59½+ and 5-year rule satisfied) are completely tax-free, including all growth. The 2026 employee contribution limit is $24,500 — the same as Traditional 401(k).
Roth 401(k) vs Traditional: which is better?
Roth generally wins if you expect higher taxes in retirement or you are early in your career; Traditional wins if you expect lower taxes in retirement or need the current-year deduction. Many savers split contributions across both for tax diversification.
Is there an income limit for Roth 401(k)?
No. Unlike a Roth IRA (which phases out above $150,000 single / $236,000 married in 2026), a Roth 401(k) has no income limit to contribute. This makes it the only tax-free retirement vehicle available to high earners.
Does my employer's match go into my Roth 401(k)?
Before SECURE 2.0 (2022), employer matches on Roth 401(k) contributions had to go into a pre-tax Traditional bucket. SECURE 2.0 now allows employers to offer Roth matching, but the employee must elect it and the match amount is immediately taxable.
Further Reading
- Reviewed by David Jones
- Limits Updated for 2026 IRS contribution caps
- Formulas Verified quarterly
Review & Methodology
- Reviewed by David Jones (calculator methodology).
- Updated for 2026 IRS contribution limits (refreshed after each annual IRS notice).
- Core calculator formulas are re-tested quarterly; limit-driven logic is checked when IRS guidance changes.
- Educational projections only — not investment, tax, or wealth-management advice. Calculations run locally in your browser.