Roth vs Traditional: Why Most Comparisons Are Rigged

By Alamzeb Khan · Updated August 2026 · 7 min read · Roth vs Traditional Calculator →

The result nobody believes

Start with the finding that makes this whole decision clearer.

Put $7,000 of your own money in. Leave it 30 years at 7%. Assume a 24% tax rate now and 24% in retirement.

Identical. Not similar - the same number, to the penny. You can check it in the Roth vs Traditional calculator.

The reason is not a coincidence. Taking 24% off at the start and growing what is left gives exactly the same answer as growing the whole thing and taking 24% off at the end. Multiplication does not care about the order.

Once you accept that, the real question becomes obvious: the only thing that matters is whether your tax rate changes.

Why the Traditional puts in more

Look at that table again. The Roth got $7,000 and the Traditional got $9,211 - from the same $7,000 out of your bank account.

That is not a trick. A Traditional contribution is made with money that has not been taxed. To spend $7,000 of after-tax money on a Roth, you had to earn about $9,211 and pay $2,211 in tax first. Put that same pre-tax $9,211 into a Traditional instead and the whole lot goes across.

This is the step most comparisons skip. They put $7,000 into each and declare the Roth the winner, having quietly ignored that the Traditional route left $2,211 still in your pocket.

What actually decides it

Change the tax rates and the answer moves - a lot:

Notice the Roth column never changes. It cannot - the tax was already paid, so future rates are irrelevant to it. All the movement is in the Traditional column, and all of it comes from what rate applies on the way out.

So the rule is short:

• Expect a lower rate later? Traditional.
• Expect a higher rate later? Roth.
• No idea? Split them, and stop worrying.

When the Roth genuinely wins on the other framing

There is a second way to compare: put the same headline amount into each - $7,000 in both - and invest the Traditional refund in an ordinary taxable account.

Here the Roth wins by $3,275, even with matching tax rates. Why? Because the side account is taxable - its growth gets taxed along the way, so it cannot keep up with money growing inside a shelter.

Both framings are legitimate. Which applies to you depends on one honest question: would you actually invest the refund, or spend it? If you would invest it, the first table is your comparison. If you would spend it, the second one is.

Things that tilt it beyond the tax rate

Nobody makes you empty a Roth. From 73, a Traditional account forces withdrawals every year, taxed as income - see the RMD guide. A Roth has no such requirement while you are alive. That is a genuine advantage the arithmetic above does not capture.

Contribution limits favour the Roth in real terms. The annual limit is the same number for both, but $24,500 into a Roth is $24,500 of after-tax money - worth more than $24,500 of pre-tax money. If you are maxing out, the Roth quietly lets you shelter more.

Tax law changes. Everything above assumes today’s rules. Nobody knows what rates will be in thirty years, which is itself a decent argument for holding some of each.

What to actually do

1. Check whether your rate is likely to rise or fall. That is the whole decision. Most people earn less in retirement than while working, which points to Traditional - but a large Traditional balance forcing big withdrawals later can push you back up.
2. Get the full employer match first, whichever type it goes into. That is a bigger win than this choice - see the 401(k) guide.
3. If the two rates are close, split. The arithmetic barely moves and you buy real flexibility.
4. Be honest about the refund. If a Traditional contribution means more spending money rather than more invested money, that changes which comparison applies to you.

Run your own rates through the Roth vs Traditional calculator - it shows both framings side by side and marks the exact retirement tax rate at which the answer flips.

Common questions about roth vs traditional