How to Use This Calculator
- 1
Enter Annual Contribution
Input the total amount you contribute to your Roth 401(k) each year. The 2026 limit is $23,500 ($31,000 if age 50+).
- 2
Enter Current Roth 401(k) Balance
Provide your existing account balance, which will continue to compound tax-free.
- 3
Specify Years Until Retirement
Enter the number of years until you plan to retire to project compounding growth.
- 4
Set Annual Rate of Return
Input your expected average annual investment return. The S&P 500 has historically averaged ~7% after inflation.
- 5
Review Your Projections
See your total projected balance, tax-free growth, future value of contributions and current balance, and estimated monthly retirement income. The insights panel shows your growth multiple, retirement income estimate, and tax savings. A chart and year-by-year table show balance growth over time.
Example Calculation
A professional with $50,000 in their Roth 401(k) contributes $5,000 annually at 7% return for 20 years.
Annual Contribution
$5,000
Current Roth 401(k) Balance
$50,000
Years Until Retirement
20
Annual Rate of Return
7%
Results
Total Roth 401(k) Balance
$398,462
Tax-Free Growth
$248,462
Future Value of Contributions
$204,977
Future Value of Current Balance
$193,484
Est. Monthly Retirement Income
$1,660
Insights card shows growth multiple, retirement income estimate, and tax advantage savings.
Tips
Maximize Catch-Up Contributions
If you are age 50 or older, you can contribute an additional $7,500 beyond the standard $23,500 limit in 2026. Try entering $31,000 as your annual contribution to see the impact.
Understand the Five-Year Rule
Roth 401(k) earnings are tax-free only if the account has been open for at least 5 years AND you are age 59.5+. Plan your account opening date accordingly.
Compare Contribution Levels
Use the recent calculations history to compare different annual contribution amounts. Increasing from $5,000 to $10,000 annually at 7% over 20 years nearly doubles the contribution portion from $204,977 to $409,955.
No RMDs for Roth 401(k)
Starting in 2024, Roth 401(k) accounts are no longer subject to Required Minimum Distributions, making them even more attractive for long-term tax-free growth.
Maximizing Tax-Free Growth with a Roth 401(k)
The Roth 401(k) Calculator projects your future tax-free retirement savings by combining compound growth on your current balance with the future value of annual contributions. By inputting your contribution amount, current balance, time horizon, and expected return, you can visualize the substantial compounding growth your Roth 401(k) can achieve.
For example, contributing $5,000 annually to an account starting with $50,000, earning 7% over 20 years, results in a tax-free balance of approximately $398,462 at retirement — with $248,462 in pure investment growth.
The Roth 401(k) Growth Formula
The calculator uses two future value formulas combined:
- Future Value of Current Balance:
FV_current = current balance × (1 + r)^n - Future Value of Annual Contributions (Future Value of Annuity):
FV_contributions = annual contribution × (((1 + r)^n - 1) / r) - Total Roth 401(k) Balance:
Total = FV_current + FV_contributions
Where r is the annual rate of return (as a decimal) and n is the number of years until retirement.
Projecting a Roth 401(k) Over 20 Years
Given: Annual Contribution = $5,000, Current Balance = $50,000, Years = 20, Rate = 7%.
- Future Value of Current Balance:
$50,000 × (1.07)^20 = $50,000 × 3.8697 = $193,484 - Future Value of Contributions:
$5,000 × ((1.07^20 - 1) / 0.07) = $5,000 × (2.8697 / 0.07) = $5,000 × 40.9955 = $204,977 - Total Balance:
$193,484 + $204,977 = $398,462 - Tax-Free Growth:
$398,462 - $150,000 (total contributed) = $248,462 - Growth Multiple:
$398,462 / $150,000 = 2.7x - Estimated Monthly Retirement Income (20-year drawdown):
$398,462 / 240 months = $1,660/month
Your projected balance of $398,462 includes $248,462 in tax-free growth — a 2.7x return on your total investment.
Roth 401(k) vs Traditional 401(k)
The key difference is tax treatment. Traditional 401(k) contributions are pre-tax (reducing current income) but withdrawals are taxed. Roth 401(k) contributions are after-tax, but qualified withdrawals are completely tax-free.
For the example above, $248,462 in growth withdrawn from a Traditional 401(k) at a 22% tax rate would cost approximately $54,662 in taxes. With a Roth 401(k), that entire amount is tax-free — a significant advantage for those expecting higher tax rates in retirement.
2026 Contribution Limits and Strategies
The 2026 Roth 401(k) contribution limit is $23,500, with an additional $7,500 catch-up for those age 50 and older ($31,000 total). These limits are shared with Traditional 401(k) contributions from the same employer.
Starting in 2024, Roth 401(k) accounts are no longer subject to Required Minimum Distributions (RMDs), making them even more attractive for long-term tax-free growth. You can also contribute to both a Roth 401(k) and a Roth IRA separately, maximizing your tax-free savings potential.
Frequently Asked Questions
What is a Roth 401(k)?
A Roth 401(k) is an employer-sponsored retirement plan with after-tax contributions. Unlike a Traditional 401(k), qualified withdrawals in retirement — including all earnings — are completely tax-free. It's ideal for those who expect to be in a higher tax bracket during retirement.
What are the contribution limits for 2026?
The 2026 Roth 401(k) contribution limit is $23,500. Individuals age 50 and older can make an additional $7,500 catch-up contribution for a total of $31,000. These limits are shared with Traditional 401(k) contributions from the same employer.
How much will $5,000/year grow at 7% over 20 years?
Contributing $5,000 annually at 7% return for 20 years produces $204,977 from contributions alone. Combined with a $50,000 starting balance (which grows to $193,484), the total reaches $398,462 — with $248,462 in tax-free growth.
When are Roth 401(k) withdrawals tax-free?
Withdrawals are tax-free and penalty-free when two conditions are met: the account has been open for at least 5 years, and you are age 59.5 or older (or disabled, or the distribution goes to a beneficiary after death).
What does the insights panel show?
The insights panel displays your growth multiple (how much each $1 invested becomes), estimated monthly retirement income over a 20-year withdrawal period, and approximate tax savings compared to a taxable account at a 22% rate.
Can I contribute to both a Roth 401(k) and a Roth IRA?
Yes. The contribution limits are separate. You can contribute up to $23,500 to a Roth 401(k) and up to $7,000 to a Roth IRA in 2026, for a combined $30,500 in Roth savings. However, Roth IRA contributions have income limits while Roth 401(k) contributions do not.