Roth or Traditional: it is one comparison, not ten

The Roth versus Traditional decision gets discussed as though it involves a dozen factors. It involves one:

Is your tax rate higher now, or will it be higher when you withdraw?

Pay tax at the lower of the two. That is the entire principle. Everything else — required distributions, estate planning, contribution limits — is a refinement on top of that sentence.

What each one actually does

Traditional: you skip income tax on the money going in, it grows untaxed, and you pay ordinary income tax on everything you withdraw. Tax deferred, not avoided.

Roth: you pay income tax on the money going in, it grows untaxed, and withdrawals are tax-free. Tax paid up front, then never again.

Both shelter the growth. That is the shared benefit, and it is the large one. The only thing they disagree about is when the government takes its share.

Three scenarios, same contributions

$7,000 a year from age 35 to 65 at 7%. What changes between them is only the tax rate assumption.

Your rate is higher in retirement

22% now, 28% later. Roth after tax: $551,859. Traditional after tax: $509,408. Roth wins — you locked in the cheaper rate by paying tax early.

Your rate is lower in retirement

32% now, 22% later. Traditional after tax: $551,859. Roth after tax: $481,108. Traditional wins — you skipped the expensive rate and paid the cheap one instead.

Your rate is identical

24% both times. Roth: $537,709. Traditional: $537,709. Essentially identical, which is the mathematical proof that the rate comparison is the only thing driving the result.

Guessing your future rate

This is the genuinely hard part, and it is a forecast, not a calculation.

Points toward Roth: you are early in your career and your current rate is near its lifetime low. You expect substantial income in retirement from a pension, rental property, or a large traditional balance already accumulated. You think tax rates generally rise from here.

Points toward Traditional: you are in a peak earning year. You live in a high-tax state now and plan to retire somewhere with low or no income tax — the state difference alone can be several percentage points. Your retirement spending will be modest relative to your current income.

Note the common pattern hiding in there: many people retire on less than they earned, which genuinely does put them in a lower bracket. Traditional is the reasonable default for mid-to-late-career high earners for exactly that reason.

The considerations beyond the rate

Roth has no required minimum distributions. Traditional accounts force withdrawals starting at 73 whether you need the money or not, which can push you into a higher bracket precisely when you were trying to stay out of one.

Roth contributions can be withdrawn without penalty — the contributions, not the growth. That makes a Roth IRA a partial emergency backstop in a way a traditional account is not.

A Roth is worth more per dollar of limit. $7,000 in a Roth is $7,000 of spendable retirement money. $7,000 in a Traditional is $7,000 minus future tax. When you are contributing the maximum, the Roth quietly shelters more.

Roth is simpler to leave to heirs, who inherit it without an income tax bill attached.

When it is close, split

If your current and expected rates are within a few points, the difference is small and your forecast is not reliable enough to justify certainty. Contributing to both hedges against being wrong about tax law thirty years out, and gives you two pools to draw from in retirement — which is itself useful, because you can manage which bracket you land in year by year.

One thing that is never close: capture the full employer match first, whichever account type it lands in. A match is an immediate 50–100% return, and no tax argument competes with that.