Roth vs. Traditional Calculator (2026)

Rate in retirement	Roth	Traditional + saved tax reduction	Leads by
10%	$280,006	$314,738	Traditional $34,732
15%	$280,006	$300,738	Traditional $20,732
20%	$280,006	$286,738	Traditional $6,732
25%	$280,006	$272,738	Roth $7,268
30%	$280,006	$258,737	Roth $21,269
35%	$280,006	$244,737	Roth $35,269
40%	$280,006	$230,737	Roth $49,269

The short answer

Roth tends to gain value when your future tax rate is higher. Traditional tends to gain value when it is lower.

That rule is a useful starting point, but it is incomplete. A Traditional contribution can reduce current taxable income, while a Roth contribution is made with after-tax dollars. A fair comparison therefore asks what happens to the current tax reduction: is it invested for retirement, or quietly absorbed into spending?

The decision in one sentence

Compare the marginal tax avoided today with the marginal tax paid on future Traditional withdrawals—then include the tax reduction itself.

The calculator does this with one consistent contribution, return, fee, inflation assumption, and time horizon.

How this Roth vs. Traditional calculator works

Use the same annual contribution.The Roth and Traditional retirement accounts receive the same inflation-adjusted employee contribution.
Estimate today’s income-tax reduction.The Traditional contribution is multiplied by the current marginal rate you enter.
Model the tax reduction separately.You can view the result when it is invested in a taxable side account or when it is spent.
Apply retirement tax.The Traditional account is reduced by the assumed marginal rate on future withdrawals. A qualified Roth amount is shown tax-free.
Express the result in today’s dollars.Contributions rise with inflation and future balances are deflated to make their purchasing power easier to compare.

Simplified comparison

Roth spendable = projected Roth balance
Traditional spendable = projected pre-tax balance − retirement tax
Complete Traditional strategy = Traditional spendable + invested current-tax reductions

The taxable side account applies the selected capital-gains rate to modeled gains at the end of the horizon. Actual taxable accounts can owe taxes along the way.

Why “same contribution” and “same paycheck cost” are different

Suppose two workers each direct $10,000 to a retirement account. The Roth worker generally pays current income tax on that compensation. The Traditional worker may reduce current taxable income and keep more take-home pay. Comparing only the two retirement-account balances ignores that difference.

If the Traditional worker invests the tax reduction, the side account becomes part of the retirement strategy. If the worker spends it, Roth can appear stronger even when the future tax rate is lower. Neither behavior should be assumed silently, so the calculator lets you switch between both views.

Use a marginal tax rate, not the headline bracket alone

The useful current rate is the estimated income tax avoided by the next dollar of deductible or pre-tax contribution. It may combine a federal marginal rate and a state marginal rate, but deductions, credits, phaseouts, filing status, and state rules can change the real amount.

The retirement rate is even less certain. Traditional withdrawals can share a tax return with Social Security, pensions, wages, capital gains, RMDs, and a spouse’s income. A withdrawal can also affect the taxable portion of Social Security, Medicare IRMAA, or an ACA subsidy. The public calculator deliberately asks for one planning rate rather than pretending to complete a future tax return.

What the tax-rate crossover means

The crossover is the future marginal tax rate at which the modeled Roth amount and the complete Traditional strategy are approximately equal. Below it, Traditional plus invested tax reductions is larger. Above it, Roth is larger.

It is not a forecast of your future bracket. Use the sensitivity table to test several rates. When the result changes with a small rate adjustment, a split between Roth and Traditional contributions may be more robust than an all-or-nothing choice.

Roth and Traditional tax treatment in plain English

General federal treatment used by the illustration
Question	Roth contribution	Traditional pre-tax contribution
Included in current taxable income?	Generally yes	Generally deferred for federal income tax
Employee Social Security and Medicare tax?	Generally applies	Generally still applies
Tax on a qualified retirement distribution?	Generally excluded from gross income	Contributions and earnings are generally taxable
Annual workplace-plan contribution limit?	Roth and pre-tax elective deferrals share one combined employee limit

For 2026, the IRS says the employee elective-deferral limit for 401(k), 403(b), most 457 plans, and the federal Thrift Savings Plan is $24,500. The IRA contribution limit is $7,500. Catch-up amounts and eligibility rules can differ by age, income, plan, and account type.

What this first version does not include

Included

Current and retirement marginal-rate assumptions
Same inflation-adjusted annual contribution
Return, fee, and inflation assumptions
Invested or spent Traditional tax reduction
Simplified tax on taxable-account gains

Not included

Full federal or state tax-return calculations
Employer match and Roth employer contributions
Contribution eligibility, phaseouts, or penalties
RMDs, Social Security tax, IRMAA, or ACA effects
Changing returns, rates, laws, or withdrawal timing

The paid Snapshot can connect account choice with household income, withdrawal order, Social Security, Medicare, state taxes, and multi-year Roth conversion opportunities. AI may translate a question into reviewed inputs and explain a deterministic result, but it does not calculate or invent tax savings.

Roth vs. Traditional FAQ

Is Roth or Traditional better if my tax rate stays the same?

It can be close, but the answer depends on whether you compare equal contributions or equal take-home cost and whether the Traditional tax reduction is invested. This calculator shows both invested and spent tax-reduction outcomes instead of hiding that assumption.

Should I use my marginal or effective tax rate?

Use an estimate of the marginal rate that applies to the contribution today and to the Traditional withdrawal later. An effective rate averages tax across all income and may understate the rate on the next dollar.

Does a Traditional contribution avoid Social Security and Medicare tax?

Generally, employee pre-tax elective deferrals remain subject to Social Security and Medicare taxes. The calculator models income-tax rates only.

Are Roth withdrawals always tax-free?

No. The result assumes a qualified Roth distribution. Account type, age, holding period, distribution reason, and other rules can affect treatment. Confirm the rules for your plan or IRA.

Does this calculator include employer matching contributions?

No. Employer contributions and their tax treatment are plan-specific. This public comparison isolates the employee contribution and the current income-tax reduction.

Can I split contributions between Roth and Traditional?

Often yes when a workplace plan offers both, subject to plan terms and the combined annual limit. A split can diversify future tax exposure when the future rate is uncertain.

Official sources

Educational use only. This simplified illustration is not tax, investment, legal, or fiduciary advice and does not prepare a tax return. Rules differ across Roth IRAs, Traditional IRAs, designated Roth plan accounts, and pre-tax workplace accounts. Verify eligibility and tax treatment with official plan documents and qualified professionals before making a consequential election.

Pay tax now—or later? Compare the dollars you may actually spend.

Compare what may be spendable after tax.

The estimated break-even retirement rate is 22.4%.