Which is better, Roth or Traditional?

There is no one‑size‑fits‑all answer. On pure math, Traditional tends to win when your future tax rate is lower than your current rate, while Roth tends to win when your future rate is the same or higher. Many people split contributions to hedge uncertainty.

Are contribution limits or income phaseouts modeled?

No. The calculator focuses on the tax effect per dollar of contribution. You still need to respect annual contribution limits, income eligibility rules, and plan‑specific constraints.

Does this model RMDs, Roth conversions, or Social Security interactions?

No. Those advanced planning topics can materially affect outcomes, but they require more complex modeling. Use this tool as a starting point, then layer in RMD and conversion strategies with a professional if needed.

How do employer matches affect the comparison?

Employer matches typically go into pre‑tax Traditional buckets regardless of your own contribution type. This calculator looks at the tax treatment of your contribution itself, not employer contributions.

Should I include state taxes?

You can fold state and local taxes into your current and future tax rates if you want a combined view. For example, if you pay 22% federal and 5% state now, you might enter 27% as your current rate.

finance calculator

Roth vs Traditional IRA Calculator

Compare Roth vs Traditional outcomes by modeling current tax savings, future tax rates, and growth over time.

Results

Traditional after-tax at retirement: $20,601
Roth value at retirement: $25,751
Current tax savings (Traditional): $1,320
Current tax rate: 22.00%
Expected retirement tax rate: 20.00%

Overview

Choosing between Roth and Traditional retirement contributions is essentially a bet about when you want to pay taxes: now or later. Traditional contributions can lower your taxable income today, but withdrawals in retirement are taxed. Roth contributions are made with after‑tax dollars, but qualified withdrawals are tax‑free. The key question is whether your tax rate will be higher or lower in the future compared with today.

This Roth vs Traditional IRA calculator gives you a structured way to think about that trade‑off. You enter a contribution amount, your current marginal tax rate, an expected marginal rate in retirement, your time horizon, and an assumed rate of return. The tool then estimates the after‑tax value of a Traditional contribution at retirement, the value of a Roth contribution, and the current‑year tax savings from choosing Traditional. That lets you see, side by side, the immediate tax benefit and the long‑term after‑tax outcome.

How to use this calculator

Enter the contribution amount you are considering for Roth vs Traditional treatment (for example, $6,000). This can be within annual contribution limits for IRAs or similar pre‑tax vs after‑tax choices in workplace plans.
Enter your current marginal tax rate—the rate that applies to the last dollar you earn today. This drives the value of the Traditional tax deduction.
Enter the marginal tax rate you expect in retirement. You can model multiple scenarios: lower, similar, or higher than your current rate.
Enter the number of years the money will grow until retirement and an expected annual return (before inflation and fees).
Review the outputs: Traditional after‑tax value at retirement, Roth value, and current‑year tax savings from a Traditional contribution.
Adjust inputs (especially tax rates and years) to test alternate futures and see how sensitive the comparison is to changes in your assumptions.

Inputs explained

Contribution: The dollar amount you plan to contribute on a pre‑tax or Roth basis. This tool compares the tax treatment of the same contribution amount rather than enforcing annual limits.
Current marginal tax rate (%): Your marginal tax rate today—the rate that applies to the last dollar of your income, combining federal (and optionally state) if you choose. It determines how valuable a current‑year Traditional deduction is.
Expected retirement tax rate (%): Your estimated marginal tax rate in retirement. If you expect lower income, you might assume a lower rate; if you expect higher income or higher future tax policy, you might assume a similar or higher rate.
Years to grow: The number of years your contribution will remain invested before retirement withdrawals begin. Longer horizons magnify the impact of tax‑free or tax‑deferred growth.
Expected annual return (%): An assumed average annual investment return before taxes. This is applied equally to both Roth and Traditional paths so you are comparing tax treatment rather than investment choices.

How it works

For a Traditional contribution, you get a current‑year tax deduction equal to Contribution × Current tax rate. That’s the upfront tax savings for putting money into a pre‑tax account instead of a taxable account.

Inside the Traditional IRA, contributions grow tax‑deferred. We model the future pre‑tax balance as Future_pre_tax = Contribution × (1 + r)^n, where r is the annual return (as a decimal) and n is the number of years to grow.

When you withdraw from a Traditional IRA in retirement, the entire distribution is typically taxed as ordinary income. We approximate the after‑tax value as Traditional_after_tax = Future_pre_tax × (1 − Future tax rate).

For a Roth contribution, you do not get a tax deduction now—your contribution is after‑tax dollars. However, qualified withdrawals in retirement are tax‑free. We model Roth_after_tax = Contribution × (1 + r)^n, using the same growth assumptions.

By comparing Traditional_after_tax to Roth_after_tax, you can see which contribution type leaves you with more spending power at retirement under your tax‑rate assumptions.

We also report Current tax savings (Traditional) = Contribution × Current tax rate, so you can weigh the value of an immediate tax reduction against the long‑term trade‑off in retirement.

Formula

Future_pre_tax = Contribution × (1 + r)^n
Traditional_after_tax = Future_pre_tax × (1 − Future_tax_rate)
Roth_after_tax = Contribution × (1 + r)^n
Current_tax_savings_Traditional = Contribution × Current_tax_rate

When to use it

Deciding whether to direct this year’s IRA or 401(k) contributions to Roth or Traditional buckets based on your tax expectations.
Testing scenarios where your retirement tax rate is higher, equal to, or lower than your current marginal rate to see how sensitive the choice is.
Quantifying the dollar value of the immediate Traditional tax deduction and comparing it with long‑term after‑tax balances.
Helping younger earners or those temporarily in a low bracket see why Roth contributions can be appealing if future income is likely to be higher.
Evaluating whether to diversify between Roth and Traditional contributions rather than choosing a single approach, by seeing how each side behaves under different assumptions.

Tips & cautions

Use marginal tax rates, not average or effective rates, because contribution decisions affect your top dollars of income. You can approximate these from tax software or bracket charts.
If you expect to be in a lower bracket in retirement (for example, much lower income, no dependents, and paid‑off mortgage), Traditional often looks better on pure math because you deduct at a high rate now and pay at a lower rate later.
If you expect your tax rate to be the same or higher in retirement, Roth contributions often win because you pay tax now at a lower or equal rate and enjoy tax‑free withdrawals later.
Revisit your assumptions periodically—job changes, promotions, relocations, and tax‑law changes can all shift the Roth vs Traditional calculus.
Consider non‑math factors too: Roth accounts can provide more flexibility around required minimum distributions (RMDs), estate planning, and future tax‑policy uncertainty.
Simplified model; it does not enforce IRA contribution limits, income phaseouts, catch‑up contributions, or interactions with employer plans and matches.
Assumes constant tax rates and investment returns over the entire timeframe; real life includes volatility, tax‑law changes, and bracket creep.
Does not model required minimum distributions (RMDs), Roth conversions, Social Security interactions, or the impact of other retirement income sources.
Treats state and local taxes implicitly through your chosen tax rates; it does not separately account for differences between current and retirement states of residence.
Focuses on single, lump‑sum contributions. Ongoing annual contributions, changing salaries, and sequence‑of‑returns risk require more detailed planning.

Worked examples

$6,000 contribution, 22% now, 20% in retirement, 25 years, 6% return

Future_pre_tax ≈ 6,000 × (1.06)^25 ≈ $25,751.
Traditional_after_tax ≈ 25,751 × (1 − 0.20) ≈ $20,601.
Roth_after_tax ≈ 25,751 (no tax on qualified withdrawals).
Current_tax_savings_Traditional ≈ 6,000 × 0.22 = $1,320.
Interpretation: Roth leaves you with more after‑tax dollars at retirement in this scenario, but Traditional delivers $1,320 of tax savings today.

$6,500 contribution, 24% now, 15% in retirement, 20 years, 7% return

Future_pre_tax ≈ 6,500 × (1.07)^20 ≈ $25,226.
Traditional_after_tax ≈ 25,226 × (1 − 0.15) ≈ $21,442.
Roth_after_tax ≈ 25,226.
Current_tax_savings_Traditional ≈ 6,500 × 0.24 = $1,560.
Interpretation: because your future tax rate (15%) is meaningfully lower than your current rate (24%), the Traditional path looks relatively more attractive on a pure tax‑rate basis.

Low current bracket, higher expected retirement rate

Suppose you are early‑career with a 12% current marginal rate, expect a 22% retirement rate, plan to invest for 30 years, and use a 7% return.
Roth contributions mean paying 12% tax now and avoiding 22% later, while Traditional would save only 12% now but lose 22% at withdrawal.
Under these assumptions, the calculator will generally show Roth_after_tax ahead of Traditional_after_tax, reinforcing the case for Roth in low‑income years.

Deep dive

Use this Roth vs Traditional IRA calculator to compare the immediate tax savings of a Traditional contribution with the after‑tax value of both Roth and Traditional accounts at retirement.

Enter a contribution amount, your current and expected retirement tax rates, years to grow, and an assumed return to see which path looks better under different tax‑rate scenarios and how much the Traditional deduction is worth today.

The tool helps you visualize the core trade‑off: pay taxes now in exchange for tax‑free withdrawals later (Roth), or save on taxes today and potentially pay more—or less—later (Traditional), depending on how your future tax rate compares to your current one.

FAQs

Which is better, Roth or Traditional?: There is no one‑size‑fits‑all answer. On pure math, Traditional tends to win when your future tax rate is lower than your current rate, while Roth tends to win when your future rate is the same or higher. Many people split contributions to hedge uncertainty.
Are contribution limits or income phaseouts modeled?: No. The calculator focuses on the tax effect per dollar of contribution. You still need to respect annual contribution limits, income eligibility rules, and plan‑specific constraints.
Does this model RMDs, Roth conversions, or Social Security interactions?: No. Those advanced planning topics can materially affect outcomes, but they require more complex modeling. Use this tool as a starting point, then layer in RMD and conversion strategies with a professional if needed.
How do employer matches affect the comparison?: Employer matches typically go into pre‑tax Traditional buckets regardless of your own contribution type. This calculator looks at the tax treatment of your contribution itself, not employer contributions.
Should I include state taxes?: You can fold state and local taxes into your current and future tax rates if you want a combined view. For example, if you pay 22% federal and 5% state now, you might enter 27% as your current rate.

Related calculators

finance

Retirement Needs Calculator

Estimate the nest egg required to fund retirement spending at a target withdrawal rate.

finance

Savings Rate Calculator

Find your monthly savings rate and annualized savings from income and savings.

This Roth vs Traditional calculator is for educational and planning purposes only. It uses simplified assumptions about tax rates, returns, and contribution patterns and does not account for all IRS rules or individual circumstances. Always consult a qualified tax or financial professional before making retirement contribution decisions.