401(k) vs IRA: Key Differences and Which to Use First
Both 401(k) and IRA accounts offer powerful tax advantages for retirement savings — but they work differently, have different limits, and serve different roles in a comprehensive retirement strategy. Most retirement savers should use both. But knowing which to prioritize, and why, can make a significant difference in your long-term wealth accumulation.
The Core Comparison
| Feature | 401(k) | Traditional IRA | Roth IRA |
|---|---|---|---|
| 2024 Contribution Limit | $23,000 ($30,500 if 50+) | $7,000 ($8,000 if 50+) combined | |
| Employer Match? | Often yes | No | No |
| Tax on Contributions | Pre-tax (traditional) or after-tax (Roth 401k) | Pre-tax (deductible) | After-tax |
| Tax on Withdrawals | Taxed as income | Taxed as income | Tax-free |
| Required Min Distributions? | Yes, at age 73 | Yes, at age 73 | No |
| Investment Options | Limited (plan menu) | Almost unlimited | Almost unlimited |
| Income Limits | None | Deductibility phases out at high income | Contribution phases out at high income |
| Early Withdrawal | 10% penalty + taxes before 59½ | 10% penalty + taxes before 59½ | Contributions can be withdrawn anytime penalty-free |
Understanding the Tax Difference
Traditional accounts (pre-tax): You contribute money before paying income tax, reducing your taxable income now. In retirement, withdrawals are taxed as ordinary income. You get the tax break today and pay later.
Roth accounts (after-tax): You contribute money you've already paid taxes on. In retirement, all withdrawals — contributions and all earnings — are completely tax-free. You pay taxes now and enjoy tax freedom later.
Which is better depends on whether you'll be in a higher or lower tax bracket in retirement than you are today. If higher in retirement: Roth wins. If lower in retirement: Traditional wins. If you're unsure (most people are): having both provides valuable tax diversification.
2024 IRA Income Limits
Roth IRA eligibility phases out at:
- Single filers: $146,000-$161,000 MAGI
- Married filing jointly: $230,000-$240,000 MAGI
Traditional IRA deductibility (if covered by workplace plan) phases out at:
- Single filers: $77,000-$87,000 MAGI
- Married filing jointly: $123,000-$143,000 MAGI
High earners above the Roth IRA income limit can use a "backdoor Roth" strategy — contributing to a traditional IRA and then converting to Roth. This is legal but involves some complexity around existing pre-tax IRA balances.
The Optimal Contribution Order
Given limited savings capacity, most financial advisors recommend this priority order:
- 401(k) up to employer match: This is a guaranteed 50-100% return on your contribution — free money. Never leave this on the table under any circumstances. It outperforms any other investment by a massive margin.
- Roth IRA maximum ($7,000): Tax-free growth on contributions invested for decades is extraordinarily powerful. Max it out, especially if you're young and in a lower tax bracket.
- 401(k) maximum (remaining $16,000): Continue filling your 401(k) to the $23,000 limit. Pre-tax contributions reduce your current tax bill significantly.
- HSA maximum (if eligible): Triple tax advantage (pre-tax in, tax-free growth, tax-free out for medical) makes the HSA arguably the most tax-efficient account available.
- Taxable brokerage account: After maxing all tax-advantaged options, invest additional savings in a taxable account.
The 401(k) Employer Match: Absolutely Never Leave It Behind
If your employer matches 50% of your contributions up to 6% of salary, that match represents an instant 50% return on the matched portion. If you earn $70,000 and contribute 6% ($4,200), your employer adds $2,100 — that's a 50% guaranteed return before any market gains. No investment, anywhere, offers anything close to this risk-adjusted return.
Failing to capture the full employer match is the single most common and most costly retirement planning mistake. If you're not contributing enough to capture the full match, make this your first financial priority above everything else.
Investment Choice: IRA Wins Over 401(k)
One significant advantage of IRAs over 401(k)s is investment flexibility. A 401(k) is limited to the funds selected by your employer's plan — often a relatively small menu that may include high-fee options. IRAs at institutions like Fidelity, Vanguard, or Schwab give you access to virtually any publicly traded security, including the lowest-cost index funds available.
If your 401(k) plan is dominated by high-expense-ratio funds (above 0.5%), this is an additional argument for maximizing your Roth IRA before going beyond the match in your 401(k).
Roth IRA as Emergency Backup
One often-overlooked advantage of the Roth IRA: you can withdraw your contributions (not earnings) at any time, for any reason, with no taxes or penalties. This makes the Roth IRA serve a dual purpose: retirement account with tax-free growth AND a last-resort emergency backup that doesn't carry a penalty for contributions.
This flexibility makes the Roth IRA particularly valuable for younger investors who worry about locking money away until 59½.
Project Your Retirement Savings
Use our retirement calculator to see how your 401(k) and IRA contributions add up over time.
Calculate →The Bottom Line
401(k) and IRA accounts serve complementary roles in retirement planning. Start with 401(k) contributions to the full employer match — this is non-negotiable free money. Then maximize your Roth IRA for tax-free growth. Then fill the rest of your 401(k) capacity. Together, these accounts can shelter tens of thousands of dollars annually from taxes while building the wealth you'll need for a financially secure retirement.