🇺🇸 US Retirement

Roth 401k vs Traditional 401k — tax now or tax later?

Both reduce what you owe eventually. The question is whether you pay tax on your contributions now, or on your withdrawals in retirement — and that depends entirely on which tax rate will be higher.

✓ No products to sell ✓ Knows US finance ✓ Free, forever

The Roth vs Traditional 401k debate is genuinely one of the most important financial decisions for US employees — and one of the most oversimplified. The answer is not "Roth is always better" or "Traditional always wins for high earners." It depends on your current tax bracket, your expected retirement income, and factors you cannot predict with certainty.


The core difference

When you pay tax is the whole question

FeatureTraditional 401kRoth 401k
ContributionsPre-tax — reduces taxable income todayAfter-tax — no tax benefit today
GrowthTax-deferred — no tax until withdrawalTax-free — no tax ever on growth
Withdrawals in retirementTaxed as ordinary incomeTax-free (if 59.5+ and account 5+ years old)
Required minimum distributionsYes, starting at age 73No RMDs on Roth 401k (unlike Roth IRA)
Income limitsNoneNone (unlike Roth IRA which has income limits)
Employer matchAlways goes in pre-tax (Traditional)Employer match is always Traditional, regardless of your choice

When Roth wins

Pay tax now at a lower rate than you will in retirement

If you are in the 22% bracket today and expect to be in the 32% bracket in retirement (because of investment income, rental income, or Social Security), paying tax now at 22% is a bargain. Every dollar you put into Roth locks in the lower rate permanently.
1
You are early in your career with lower income now

Most people earn more in their peak working years than in their 20s. If your tax bracket is likely to be higher in 10–20 years, locking in the current lower rate via Roth contributions has compounding value.

2
You expect significant non-401k retirement income

Social Security, rental income, pension payments, and investment dividends all push up taxable income in retirement. Large Traditional 401k withdrawals on top of these can push you into a high bracket. Roth withdrawals are invisible to the IRS.

3
Tax diversification — valuable regardless of bracket prediction

Tax law changes. Having both Traditional and Roth balances in retirement gives you flexibility to draw from whichever is more tax-efficient in any given year. This optionality has value even if you cannot predict future rates.


When Traditional wins

Take the deduction now if your bracket is at its peak

If you are in your highest-earning years — 35% or 37% bracket — and expect to retire with a modest withdrawal rate, the Traditional deduction today is worth more than the Roth flexibility in retirement. A dollar of tax deferred from the 37% bracket now, withdrawn in the 22% bracket in retirement, saves 15 cents on the dollar.

The employer match is always Traditional

Regardless of whether you choose Roth or Traditional for your own contributions, your employer's matching contributions go into a Traditional (pre-tax) account. This means everyone with an employer match has some Traditional 401k balance and the forced tax diversification that comes with it. If your employer matches generously, you may already have significant Traditional exposure even if you contribute Roth.

Converting later is possible, but not always efficient

You can roll Traditional 401k funds into a Roth IRA (a Roth conversion) after leaving an employer or in retirement. However, the converted amount is taxed as income in the year of conversion. Converting large amounts in high-income years can push you into higher brackets and may trigger Medicare surcharges. Roth conversions work best in low-income years — for example, early retirement before Social Security begins.

Which 401k type is right for your income and situation?

The answer depends on your current bracket, expected retirement income, and whether your employer offers Roth matching. Ask Franky to work through it with you.

Ask Franky about this →
Free to use No products to sell US-specific guidance