401(k) vs Roth IRA: A Complete Comparison
Choosing between a traditional 401(k) and a Roth IRA is one of the most consequential retirement planning decisions you will make. Both accounts offer significant tax advantages, but they work in fundamentally different ways. The right choice depends on your current income, expected future tax rate, employer match, and personal financial goals. This guide breaks down every difference and provides a decision framework to help you choose.
Model your own retirement scenarios with our 401(k) calculator and Roth IRA calculator.
Side-by-Side Comparison for 2026
| Feature | Traditional 401(k) | Roth IRA |
|---|---|---|
| Employee Contribution Limit | $24,000 | $7,000 |
| Catch-Up (Age 50+) | $7,500 ($11,250 for 60-63) | $1,000 |
| Tax on Contributions | Pre-tax (reduces current taxable income) | After-tax (no current deduction) |
| Tax on Growth | Tax-deferred | Tax-free |
| Tax on Withdrawals | Taxed as ordinary income | Tax-free (if qualified) |
| Income Limits | None | $161,000 single / $240,000 married (phase-out) |
| Employer Match | Yes (if offered) | No |
| Required Minimum Distributions | Yes, starting at age 73 | No (eliminated by SECURE 2.0) |
| Early Withdrawal Penalty | 10% + income tax before age 59 1/2 | Contributions anytime; earnings penalty before 59 1/2 |
| Available Through | Employer plan only | Any brokerage (self-directed) |
How the Tax Treatment Differs
Traditional 401(k): Tax Now, Pay Later
Contributions to a traditional 401(k) are made with pre-tax dollars. If you earn $75,000 and contribute $10,000, your taxable income drops to $65,000. You save on taxes today. However, when you withdraw money in retirement, every dollar is taxed as ordinary income at your then-current rate. Both the original contributions and all investment growth are taxed upon withdrawal.
Roth IRA: Pay Now, Tax-Free Later
Roth IRA contributions are made with after-tax dollars, meaning there is no upfront deduction. If you earn $75,000 and contribute $7,000, your taxable income remains $75,000. The benefit comes in retirement: qualified withdrawals, including all investment growth, are completely tax-free. You never pay taxes on the gains.
Dollar-for-Dollar Example
Suppose you have $10,000 to invest and are in the 22% federal tax bracket:
- Traditional 401(k): You contribute the full $10,000 pre-tax. After 30 years at 7% annual growth, it becomes $76,123. When you withdraw, you owe 22% tax (assuming the same bracket), leaving you $59,376.
- Roth IRA: You first pay 22% tax on $10,000, leaving $7,800 to contribute. After 30 years at 7% growth, it becomes $59,376. You withdraw it all tax-free: $59,376.
At the same tax rate, the result is identical. The Roth wins when your future tax rate is higher. The traditional 401(k) wins when your future rate is lower.
The Employer Match Advantage
The 401(k) has one enormous advantage that the Roth IRA cannot match: employer contributions. If your employer matches 50% of contributions up to 6% of salary, that is free money. On a $75,000 salary, contributing 6% ($4,500) earns a $2,250 match. That is an instant 50% return before any investment growth.
Rule of thumb: Always contribute enough to your 401(k) to capture the full employer match before directing money to a Roth IRA. Leaving match money on the table is the single costliest retirement planning mistake.
Income Limits: Roth IRA Phase-Outs
The Roth IRA has income limits that restrict or eliminate direct contributions for high earners. For 2026:
| Filing Status | Full Contribution | Phase-Out Range | No Direct Contribution |
|---|---|---|---|
| Single / Head of Household | Under $150,000 | $150,000 - $165,000 | Over $165,000 |
| Married Filing Jointly | Under $236,000 | $236,000 - $246,000 | Over $246,000 |
| Married Filing Separately | N/A | $0 - $10,000 | Over $10,000 |
If your income exceeds these limits, you may still be able to use a backdoor Roth IRA strategy: contribute to a traditional (non-deductible) IRA and then convert it to a Roth. The 401(k) has no income limits for contributions.
Required Minimum Distributions (RMDs)
Starting at age 73, you must begin taking required minimum distributions from a traditional 401(k). These withdrawals are mandatory and taxable, even if you do not need the money. This can push you into a higher tax bracket in retirement.
The Roth IRA has no RMDs during the owner's lifetime, thanks to the SECURE 2.0 Act (which also eliminated RMDs from Roth 401(k) accounts starting in 2024). This makes the Roth IRA a powerful estate planning tool, as the money can continue growing tax-free for decades.
Withdrawal Rules
Traditional 401(k)
- Withdrawals before age 59 1/2 incur a 10% early withdrawal penalty plus income tax
- Exceptions: disability, separation from service after age 55, substantially equal payments
- Loans may be available (up to $50,000 or 50% of vested balance)
Roth IRA
- Contributions (not earnings) can be withdrawn anytime, tax-free and penalty-free
- Earnings withdrawn before 59 1/2 may be subject to tax and a 10% penalty
- The account must be open for at least 5 years for qualified distributions
- First-time home purchase exception: up to $10,000 of earnings
This flexibility makes the Roth IRA a useful emergency backup fund, though you should avoid withdrawing retirement savings if possible.
Decision Framework: Which Should You Choose?
Choose the Traditional 401(k) When:
- Your employer offers a match (at least up to the match amount)
- You are in a high tax bracket now (32% or above) and expect a lower bracket in retirement
- You need the current tax deduction to reduce your AGI
- Your income exceeds Roth IRA limits and you do not want to use backdoor strategies
- You plan to retire in a no-income-tax state
Choose the Roth IRA When:
- You are in a lower tax bracket now (10%, 12%, or 22%) and expect higher income later
- You are early in your career with decades of tax-free growth ahead
- You want no RMDs in retirement for maximum flexibility
- You value the ability to withdraw contributions penalty-free
- You want to diversify your tax exposure in retirement (some pre-tax, some Roth)
The Best Strategy for Many People: Both
The optimal approach for many workers is to do both:
- Contribute to your 401(k) up to the employer match
- Max out your Roth IRA ($7,000 in 2026)
- Return to the 401(k) and contribute more if you can afford it
This gives you tax-diversification in retirement: you can withdraw from the traditional 401(k) up to a certain tax bracket and supplement with tax-free Roth IRA withdrawals.
Do Not Forget the Roth 401(k)
Many employers now offer a Roth 401(k) option that combines the higher contribution limits of a 401(k) ($24,000 in 2026) with the tax-free withdrawal benefit of a Roth. There are no income limits. This can be an excellent option if you want Roth treatment but have already maxed out your Roth IRA or earn too much to contribute directly.
Use our 401(k) calculator to see how different contribution levels affect your take-home pay, or model Roth IRA growth with our Roth IRA calculator. For a complete view of how retirement contributions affect your paycheck, try our take-home pay calculator.