Roth vs Traditional IRA Calculator

Compare the timing of IRA taxes with the same gross annual contribution, years to grow, return assumption, and current versus retirement tax rates.

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IRA comparison assumptions

Annual gross contribution ($) i Use your best current estimate; lender and account terms control.
Years to grow i Use your best current estimate; lender and account terms control.
Expected annual return (%) i Use your best current estimate; lender and account terms control.
Current marginal tax rate (%) i Use your best current estimate; lender and account terms control.
Retirement tax rate (%) i Use your best current estimate; lender and account terms control.

How to use this calculator

Enter the gross annual amount you would direct to either type of IRA.
Set the years and return assumption.
Compare the simplified after-tax futures under your current and retirement tax-rate assumptions.

Results explained

Traditional IRA contributions are modeled as pre-tax dollars that grow and are taxed at withdrawal. Roth contributions are reduced by current tax before growth, then treated as tax-free in this simplified qualified-withdrawal sketch.

Quick reference: IRA tax timing

The comparison isolates tax timing; deductibility and eligibility are separate questions.

Item	Detail
Traditional after-tax future	Gross contribution growth × (1 − retirement tax)
Roth after-tax future	Gross contribution × (1 − current tax), then growth
Main driver	Current tax rate versus retirement tax rate

IRA deduction limits, Roth income limits, conversion rules, employer plans, state taxes, and inflation are not modeled.

How it’s built

Each side uses annual end-of-year contributions compounded at the selected return. Traditional value is reduced by retirement tax after growth; Roth is reduced by current tax before growth.

Example

At a 24% current rate and 18% retirement rate, a traditional IRA can have a tax-timing advantage under these assumptions; equal tax rates make the simplified results converge.

FAQ

Is a traditional IRA contribution deductible?

Not always. Income and workplace-plan rules can limit deductibility.

Does Roth always win when taxes rise?

A higher retirement tax rate can favor Roth in this model, but eligibility and cash-flow details matter.

Why not include a 401(k) match?

This is an IRA-only comparison; employer matching has separate rules.