What is a Roth vs Traditional?
Roth and Traditional are two tax treatments for the same retirement accounts (IRAs and 401(k)s). Traditional contributions are deducted from your taxable income now, grow tax-deferred, and are taxed as ordinary income when you withdraw. Roth contributions get no deduction now, but grow and are withdrawn completely tax-free.
Because the money grows identically in both, the choice isn't about returns — it's about when you'd rather pay the tax: at today's rate or at your rate in retirement.
Why it matters
This single decision can swing your after-tax retirement income by a meaningful margin, and it's widely misunderstood. People default to Roth because 'tax-free sounds better,' or to Traditional because 'a deduction now feels good' — without checking which actually leaves them more money.
The honest answer is a clean rule: it hinges entirely on your tax rate now versus later. High earners at peak income often benefit from the Traditional deduction and a likely lower retirement rate; younger or lower-income savers, who may face higher rates later, often benefit from locking in today's low rate with Roth.
What to do next
Estimate your marginal tax rate today and a realistic rate for retirement — remember retirement income (withdrawals, Social Security, pensions) determines the latter, and it's often lower than your peak-earning rate. Enter both and see which account wins and by how much.
If they're close, or you're unsure about future tax law, splitting contributions between Roth and Traditional is a sound hedge. Then use the 401(k) calculator to apply this choice to your workplace plan, and the retirement calculator to confirm your overall savings are on track.
Frequently asked questions
Should I choose Roth or Traditional?
It depends on whether your tax rate will be higher or lower in retirement than it is now. If you expect a lower rate later (common for high earners near peak income), Traditional's upfront deduction wins. If you expect a higher rate later (common for younger savers early in their careers), Roth's tax-free withdrawals win. When the rates are equal, they're identical.
What's the difference between Roth and Traditional?
Traditional contributions are pre-tax: you deduct them now and pay income tax when you withdraw in retirement. Roth contributions are after-tax: you pay tax now, and qualified withdrawals — including all the growth — are completely tax-free. Same accounts, opposite tax timing.
Why does the break-even depend only on the tax rate?
Because for the same pre-tax contribution, both accounts grow identically. The only difference is when you pay tax and at what rate. Mathematically, Roth's after-tax value is the balance times (1 − today's rate), and Traditional's is the balance times (1 − retirement rate). Whichever rate is smaller leaves you more.
Does the Roth 'lose' the upfront tax deduction?
Yes, and that's the trade. Roth gives up the deduction now in exchange for tax-free growth and withdrawals later. This calculator accounts for that by comparing the same pre-tax contribution — so the comparison is apples-to-apples and comes down purely to your rate now vs later.
Are there other reasons to pick Roth?
Beyond the tax math, Roth accounts have no required minimum distributions in the owner's lifetime, offer tax-free inheritance to heirs, and provide tax diversification — letting you control your taxable income in retirement. Many savers split contributions to hedge against uncertain future tax rates.
What if I can't predict my future tax rate?
You're not alone — nobody can predict tax law decades out. That uncertainty is exactly why splitting contributions between Roth and Traditional is popular: it hedges the bet and gives you flexibility to draw from whichever account is more tax-efficient in a given retirement year.
Compares equal pre-tax contributions: Roth after-tax = balance × (1 − current rate); Traditional = balance × (1 − retirement rate) (2026).