🏦 The Fundamental Difference: When You Pay Tax
Both accounts offer tax advantages for retirement investing. The core difference is when you pay tax:
| Feature | Traditional 401k | Roth IRA | Roth 401k |
|---|
| Contributions | Pre-tax (reduces taxable income now) | After-tax (no deduction) | After-tax (no deduction) |
| Investment growth | Tax-deferred | Tax-free forever | Tax-free forever |
| Withdrawals in retirement | Taxed as ordinary income | Completely tax-free | Completely tax-free |
| 2025 contribution limit | $23,500 ($31,000 if 50+) | $7,000 ($8,000 if 50+) | $23,500 ($31,000 if 50+) |
| Income limit | None | $161K single / $240K married (phase-out) | None |
| Required minimum distributions | Yes, starting at age 73 | No (while original owner alive) | Yes (unless rolled to Roth IRA) |
| Employer match available | Yes | No | Yes (match is pre-tax) |
📋 The Recommended Priority Order
This is the order that maximizes your total wealth for most people in most situations. Follow it step by step:
1
401k to employer match — always first, always
A 50% match is an immediate 50% return. A 100% match is an immediate 100% return. No investment, no debt payoff, nothing else in personal finance produces a guaranteed return this high. Contribute at minimum enough to get every dollar of the match before doing anything else.
2
Roth IRA to the maximum ($7,000 in 2025)
After the employer match, the Roth IRA is almost always the better account for the next $7,000. Tax-free growth for decades is extraordinary valuable. Flexibility (contributions can be withdrawn anytime) is valuable. No RMDs at 73 is valuable. Open at Fidelity, Schwab, or Vanguard.
3
HSA if you have a high-deductible health plan
Triple tax advantage: pre-tax in, tax-free growth, tax-free for medical expenses. The most tax-efficient account in existence. $4,300 individual / $8,550 family in 2025. Invest the HSA — don't let it sit in cash.
4
Back to 401k — fill it to the $23,500 maximum
After the Roth IRA and HSA are maxed, return to the 401k and contribute up to the $23,500 annual limit. Even in a mediocre 401k plan with limited investment choices, the tax deferral is valuable enough to max before investing in a taxable brokerage account.
5
Taxable brokerage account — no limits
After all tax-advantaged accounts are maxed, invest in a standard brokerage account. No contribution limits, no withdrawal restrictions, full flexibility. Use tax-efficient investments here (total market index funds).
🤔 Traditional vs Roth: The Tax Rate Decision
For accounts where you choose (IRA, and increasingly 401k), the Roth vs Traditional decision comes down to one question: will you pay a higher or lower tax rate in retirement than you pay today?
- Pay lower taxes today than retirement → Traditional (defer tax to lower-rate future)
- Pay higher taxes today than retirement → Roth (pay tax now at lower rate)
- Not sure → Roth (flexibility and tax diversification have real value)
For most people under 40 in the 12% or 22% federal bracket, the Roth wins. You pay a modest tax rate now to permanently eliminate taxes on decades of compound growth. The 22% bracket in 2025 applies to income up to $103,350 single / $206,700 married. Most people in this bracket will not be in a lower bracket in retirement.
💡 The Roth Conversion Opportunity
If your income drops temporarily — job loss, sabbatical, early retirement before Social Security — you may be in an unusually low bracket. That's the perfect time to convert Traditional IRA or 401k money to Roth at a low tax rate. This "Roth conversion ladder" is a powerful long-term tax strategy.
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❓ Frequently Asked Questions
Can I contribute to both a Roth IRA and a 401k?+
Yes. These are separate accounts with separate contribution limits. You can max both — $23,500 in your 401k and $7,000 in a Roth IRA — for a total of $30,500 in 2025 (plus catch-up contributions if 50+). The income limit only applies to the Roth IRA, not the 401k.
What if I make too much to contribute to a Roth IRA?+
High earners (above $161K single / $240K married in 2025) can use the Backdoor Roth IRA strategy: contribute after-tax money to a Traditional IRA, then immediately convert it to Roth. This is completely legal and widely used. If your 401k offers a Roth option, there is no income limit for Roth 401k contributions.
Should I roll my old 401k into a Roth IRA?+
Rolling a Traditional 401k into a Roth IRA triggers ordinary income tax on the converted amount in the year of conversion — but all future growth is then tax-free. Whether it makes sense depends on your current tax rate, the size of the rollover, and your expected future tax rate. A CPA can help you model the specific math for your situation.
Is the Roth IRA contribution limit per person or per couple?+
Per person. A married couple can each contribute $7,000 to their own Roth IRA — $14,000 combined — as long as the couple's combined income exceeds the total contributions (you must have earned income to contribute). A non-working spouse can contribute via a Spousal IRA.