Roth vs Traditional IRA/401k Calculator
Compare Roth and Traditional retirement contributions for tax-adjusted ending value.
What this calculates
Roth: pay tax now, withdraw tax-free later. Traditional: skip tax now, pay tax later. The right pick depends on whether your tax rate at retirement will be higher or lower than today. This calculator shows after-tax ending value for both, assuming you invest the tax savings from Traditional.
Formula & how it works
Roth: FV = contribution × (1 + r)^t (tax-free withdrawal). Traditional: FV = contribution × (1 + r)^t × (1 − tax_at_retirement) + side_account, where side_account = (contribution × current_tax) × (1 + r)^t × (1 − tax_at_retirement).
Worked example
$7,000/yr for 30 yrs at 7%, 24% current tax, 22% retirement tax. Roth: $662k after tax. Traditional: $640k after tax. Roth wins slightly because rate rose less than fee drag would.
Frequently asked questions
When is Roth obviously better?
Low current tax bracket (12-22%) and expecting higher in retirement, or want tax diversification.
When is Traditional obviously better?
High current bracket (32%+) and expecting lower in retirement, or you'd otherwise contribute less because of the tax cost.
What about employer match?
Always grab full match before optimizing Roth vs Trad — it's an instant 100% return.
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