Find the optimal Roth vs. Traditional split for this year's 401(k).
About the Contribution Analyzer calculator
Traditional 401(k) contributions lower your taxes now but are taxed as income when you withdraw them in retirement. Roth contributions are made with after-tax dollars but grow and come out tax-free. The right choice hinges on your marginal tax rate today versus in retirement. This analyzer sweeps every Roth/Traditional split and finds the mix that maximizes your after-tax wealth.
Frequently asked questions
Should I contribute to a Roth or Traditional 401(k)?
Favor Traditional when your current marginal rate is higher than your expected rate in retirement, and Roth when it's lower. Many high earners do best with a mix — this tool finds the optimal split for your numbers.
What is the 2026 401(k) contribution limit?
The elective-deferral limit is $23,500 for 2026, with an additional catch-up contribution allowed if you're 50 or older.
Does my state tax rate affect the Roth vs Traditional decision?
Yes. Your combined federal plus state marginal rate now, versus in retirement, drives the decision — especially if you plan to retire in a state with a lower (or no) income tax.