Why the growth itself doesn't decide it
Both accounts invest the same way and compound at the same rate — the growth is identical. What differs is only when the tax is paid: Traditional taxes the full, larger balance once at withdrawal; Roth taxes the smaller starting contribution once, up front. Whichever tax rate is lower — now or later — is the one you want to pay at.
Using this alongside your other accounts
If you also have a workplace plan, see the 401k Calculator for employer-match projections, or the Take-Home Pay Calculator to estimate your actual current tax rate from a real paycheck.
Frequently asked questions
What is the actual difference between Roth and Traditional?
Traditional contributions go in pre-tax and are taxed when withdrawn in retirement. Roth contributions are taxed now, up front, but grow and come out completely tax-free. Same investment, opposite timing of the tax bill.
Which one comes out ahead?
If your tax rate is the same now and in retirement, they produce exactly the same after-tax result — the compounding is identical either way. Traditional wins if your retirement tax rate ends up lower than today's; Roth wins if it ends up higher.
Why would my tax rate be higher in retirement?
Required withdrawals, other retirement income, tax law changes, or simply earning more over your career than expected can all push your retirement rate above today's. Younger, lower-earning savers often lean Roth for exactly this reason.
Can I contribute to both?
Often yes, within combined contribution limits — many people split contributions to hedge against not knowing their future tax rate for certain. This calculator compares the two paths side by side to inform that split.
Last updated: June 2026