Roth and Traditional IRAs can hold similar investments, but they place income tax at different points in time. Useful Roth-versus-Traditional math has to do more than grow two balances: it should respect IRA contribution limits, direct Roth eligibility, Traditional IRA deductibility and what happens to the tax savings created by a deductible Traditional contribution.
Roth vs. Traditional IRA Calculator
See comparison breakdown
| Traditional IRA balance before retirement tax | - |
|---|---|
| Nondeductible Traditional IRA basis | - |
| Estimated retirement tax on Traditional IRA | - |
| Traditional IRA after tax | - |
| Reinvested Traditional tax savings | - |
| Roth IRA qualified after-tax value | - |
Calculation details
| Years to retirement | - |
|---|---|
| Net real annual return | - |
| 2026 age-based IRA limit | - |
| 2026 direct Roth limit | - |
| 2026 comparison contribution used | - |
| 2026 deductible Traditional amount | - |
| 2026 tax savings reinvested | - |
The comparison assumes qualified Roth withdrawals, applies 2026 IRA contribution and income rules as constant real-dollar planning rules, and reinvests any modeled Traditional IRA tax savings at the same return as the IRA. Taxes on the separate tax-savings account are not modeled. Traditional IRA basis is simplified and assumes no other traditional, SEP, or SIMPLE IRA balances affect the taxable share. Actual taxes, eligibility, future law, and retirement withdrawal patterns can differ.
How to Use the Roth vs. Traditional IRA Calculator
Enter your age, retirement age and planned annual IRA contribution, then add taxable compensation, filing status, IRA modified AGI and workplace retirement plan coverage. Filing status, MAGI, compensation and workplace coverage determine whether the planned amount fits current IRA rules and whether a Traditional contribution is deductible.
Tax & growth assumptions show the current marginal tax rate, expected retirement tax rate, investment return and inflation directly in the calculator. Timing determines much of the comparison: Roth pays tax before the money enters the account, while deductible Traditional contributions defer tax until withdrawal.
Both scenarios use the same nominal IRA contribution. Planned amounts above the direct Roth limit are reduced to the amount that can be compared directly in both accounts. Backdoor Roth contributions are deliberately excluded because conversions and the pro-rata rule require a separate analysis.
How the Comparison Keeps Roth and Traditional on Equal Footing
One common shortcut increases the Traditional IRA contribution by dividing the Roth contribution by one minus the current tax rate. Grossing up the deposit that way can push the Traditional contribution above the legal IRA limit and create an artificial advantage.
Here, the same IRA contribution enters each account. Deductible Traditional contributions generate current-year tax savings, and the model places those savings in a separate side account at the same investment return. Fair comparisons therefore need equal IRA contributions and recognition of reinvested Traditional tax savings.
Qualified Roth withdrawals are treated as tax-free at retirement. Traditional IRA withdrawals are taxed only on the modeled taxable portion. Nondeductible Traditional contributions create basis, so the model does not tax those contribution dollars a second time.
Side-account treatment is intentionally simple. It assumes Traditional tax savings are actually reinvested and grow at the same return as the IRA, while brokerage-account taxes and fees are ignored. Spending the tax savings instead would reduce the Traditional strategy’s modeled retirement value.
Consider a fully deductible Traditional contribution and a fully eligible direct Roth contribution. If the marginal tax rate is 22% both today and in retirement, the two strategies should be close when Traditional tax savings are reinvested.
Under the Traditional approach, a 22% deduction creates tax savings today while taxable withdrawals later face roughly the same rate. Roth gives up the deduction now in exchange for qualified tax-free withdrawals. Keeping the tax rates equal removes most of the mathematical advantage in either direction.
IRA Contribution and Eligibility Rules
For 2026, the IRA contribution limit is $7,500, with a $1,100 catch-up for people age 50 or older. Total contributions across Traditional and Roth IRAs share that annual limit, and eligible compensation can create a lower ceiling.
Direct Roth IRA contributions also depend on modified AGI. Single and head-of-household filers phase out from $153,000 to $168,000. Married couples filing jointly phase out from $242,000 to $252,000, while married-separate filers who lived with a spouse face the much narrower $0 to $10,000 range.
Traditional IRA contributions can still be made at higher income, but deductibility may change when the contributor or spouse is covered by a workplace retirement plan. Single filers covered at work face a 2026 deduction phaseout from $81,000 to $91,000. For a married joint filer who is covered, the range is $129,000 to $149,000.
Married contributors who are not covered at work but have a covered spouse use the $242,000 to $252,000 phaseout range on a joint return. Separate-return filers subject to workplace-plan phaseout rules generally use a $0 to $10,000 range; living apart from a spouse for the entire year can change the filing-status treatment for the deduction.
Partial deductions and reduced Roth contribution amounts are rounded under IRS worksheet rules. Current-year reductions carry into the projection with the same thresholds held constant in real terms rather than with invented future statutory limits.
Reading the Results
Roth IRA after-tax value is the projected qualified Roth balance at retirement in today’s dollars. Traditional strategy after-tax value combines the Traditional IRA after estimated retirement tax with the accumulated value of reinvested current-year tax savings.
Comparison breakdown separates the Traditional IRA balance before tax, nondeductible basis, estimated retirement tax, after-tax IRA value and reinvested tax savings. Keeping those pieces visible makes it possible to see why the Traditional result changes as deductibility or tax rates change.
Projected Roth advantage means the Roth after-tax value exceeds the modeled Traditional strategy. Traditional advantage means the after-tax Traditional IRA plus reinvested tax savings ends higher. Near tie is reserved for results within about 0.1% of each other.
Direct Roth contribution status is separate from Traditional deductibility. High MAGI can reduce a direct Roth contribution while still allowing a Traditional contribution, and workplace coverage can eliminate a Traditional deduction even when the Roth contribution remains fully available.
What Can Change the Better Choice
Future marginal tax rates remain the biggest unknown. Higher retirement tax rates generally improve the Roth side of the comparison, while lower retirement rates generally improve the value of a deductible Traditional contribution.
Deductibility can change the result just as much as the headline tax-rate assumption. Nondeductible Traditional contributions do not create the same current-year tax saving, and their future earnings remain taxable when distributed. Roth can therefore look more attractive when a direct Roth contribution is still available but the Traditional deduction has been lost.
Required minimum distributions are another difference not included in the dollar comparison. Traditional IRA owners generally face RMD rules at the applicable age, while Roth IRA owners do not have lifetime RMDs for the original owner under current law. Future withdrawal timing can therefore affect taxes beyond a single retirement tax-rate estimate.
Qualified Roth treatment also requires the applicable Roth distribution rules to be met. Early or nonqualified withdrawals can produce different tax consequences, so the projected Roth balance should not be read as automatically spendable tax-free at every age.
Tax diversification can matter even when one scenario wins by a modest amount. Holding both pre-tax and Roth assets may provide flexibility to manage taxable income in retirement rather than relying on one tax treatment for every withdrawal.
Frequently Asked Questions (FAQs)
When does a Roth IRA usually look better?
Roth tends to improve when the expected tax rate on retirement withdrawals is higher than the marginal rate paid today. Direct contribution eligibility and the availability of a Traditional deduction can change the result.
When does a Traditional IRA usually look better?
Deductible Traditional IRA contributions tend to improve when the current marginal tax rate is higher than the expected retirement tax rate, especially when the current tax savings are actually reinvested.
Why are Traditional tax savings included?
Ignoring the deduction would compare two accounts with different current cash costs. Reinvesting the modeled tax saving gives the Traditional strategy credit for its main upfront tax benefit instead of pretending the deduction disappears.
What happens if my Traditional IRA contribution is nondeductible?
Nondeductible contributions create basis rather than a current deduction. Modeled basis remains separate so it is not taxed again at retirement, while earnings on the Traditional balance remain taxable under the simplified projection.
Does the calculator include backdoor Roth contributions?
No. Backdoor Roth planning involves a Traditional IRA contribution followed by a Roth conversion and can be affected by other pretax IRA balances through the pro-rata rule.
Does the annual contribution limit apply separately to Roth and Traditional IRAs?
No. Annual IRA limits are shared across Roth and Traditional IRAs. Contributions to multiple IRAs must fit within the combined limit, subject to compensation and other eligibility rules.