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Roth Conversion Calculator 2026 — Free

Compare Roth vs Traditional IRA growth, calculate the tax cost of a Roth conversion, find your break-even retirement tax rate, and model the new 2026 SECURE 2.0 mandatory Roth catch-up rule for high earners.

Roth vs Traditional Comparison

2026 IRA limit: $7,000 ($8,000 if age 50+) Please enter a valid amount.
Please enter a valid age.
Please enter a valid age.
Please enter a valid return rate.
Your marginal federal tax rate today
Your expected marginal tax rate when withdrawing

Roth vs Traditional at Retirement

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Roth IRA (tax-free)
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Traditional IRA (after tax)
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Roth Advantage
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Break-Even Retirement Tax Rate
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Years of Growth
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Recommendation

Roth Conversion from Traditional IRA / 401k (optional)

Amount to convert from traditional IRA/401k to Roth this year Please enter a valid amount.
Your adjusted gross income before adding the conversion amount Please enter a valid income.
Auto-filled from ages above Please enter a valid number.

Roth Conversion Analysis

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Estimated Tax Due Now
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Roth Value at Retirement
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Traditional Value at Retirement (after tax)
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Net Conversion Advantage

A Roth conversion moves money from a pre-tax traditional IRA or 401(k) into a Roth IRA, triggering income tax now in exchange for completely tax-free growth and withdrawals later. The 2026 SECURE 2.0 Act now requires employees aged 50+ earning over $145,000 to make workplace retirement catch-up contributions as Roth — making this analysis more important than ever.

How It Works

  1. Enter your annual IRA contribution, age, retirement age, and return rate
  2. Select your current and expected retirement marginal tax rates
  3. Optionally enter a conversion amount to model converting existing traditional IRA funds
  4. Review the Roth vs Traditional projection, break-even rate, and conversion tax cost
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Roth vs Traditional IRA: The Core Tradeoff

Both Roth and traditional IRAs grow tax-deferred, but the timing of taxation differs fundamentally. With a traditional IRA, you may get a tax deduction today and pay income tax when you withdraw in retirement. With a Roth IRA, you contribute after-tax dollars now and pay nothing in retirement — not even on decades of growth. The math is elegantly simple: Roth wins if your tax rate in retirement is higher than today; traditional wins if the opposite is true. The break-even rate this calculator shows is the retirement tax rate at which both strategies produce identical after-tax wealth.

The 2026 SECURE 2.0 Mandatory Roth Catch-Up Rule

New for 2026: If you are age 50 or older and earned more than $145,000 in FICA wages from your employer in 2025, your workplace retirement plan catch-up contributions (401k, 403b, 457b) must be made as Roth contributions. This is mandatory under SECURE 2.0 — you cannot elect pre-tax catch-up contributions if you exceed the wage threshold. Consult your plan administrator to confirm your employer's plan supports Roth catch-up contributions.

This rule affects high-earning employees in their 50s who previously made catch-up contributions on a pre-tax basis. The standard catch-up for age 50+ is $7,500 in 2026 (total 401k limit: $31,000). For age 60–63, the "super catch-up" is $11,250 (total: $34,750). The mandatory Roth treatment increases your taxable income now but reduces it in retirement. Use this calculator to model whether the long-term Roth advantage justifies the near-term tax cost. You can see the full 2026 401k limits with our 401k calculator.

The Backdoor Roth IRA Strategy (High Earners)

Direct Roth IRA contributions are phased out for single filers with income over $150,000–$165,000 and joint filers over $236,000–$246,000 in 2026. High earners use the "backdoor Roth" workaround: contribute to a non-deductible traditional IRA ($7,000 / $8,000 if 50+), then convert it to Roth. Because the contribution was already after-tax, only any earnings since contribution are taxable — typically very little if converted promptly. There is no income limit on Roth conversions, only on direct contributions. The strategy has been used widely since 2010 and has received no definitive IRS action against it.

The Pro-Rata Rule: A Critical Backdoor Roth Trap

The pro-rata rule is the main complication in backdoor Roth conversions. If you have any pre-tax funds in traditional, SEP, or SIMPLE IRAs, the IRS treats all your IRA funds as a single pool when calculating how much of a conversion is taxable. Example: $90,000 in pre-tax IRA + $10,000 non-deductible contribution = $100,000 total. Only 10% of a conversion ($1,000 of a $10,000 conversion) is tax-free. The workaround: roll your pre-tax IRA funds into your employer's 401(k) plan (if the plan accepts rollovers) before making the non-deductible contribution.

Roth Conversion Timing Strategies

SituationConversion StrategyWhy It Works
Retired, before Social Security (ages 62–70)Large annual conversionsIncome temporarily low; fill lower brackets before SS adds income
Low-income year (job loss, sabbatical)One-time conversionTaxed at lower current rate vs higher future rate
Age 50+, FICA wages > $145KMandatory Roth catch-upRequired by SECURE 2.0 — plan for higher taxable income now
Large traditional IRA, RMD concernAnnual partial conversionsReduces future RMDs; converts pre-tax at controlled tax cost each year
Income above Roth IRA limitsBackdoor Roth annuallyBuilds Roth balance despite income limits; pro-rata rule management required

The 5-Year Rules

Roth IRAs have two separate 5-year rules. The first: a Roth IRA must be at least 5 years old before earnings can be withdrawn tax-free (regardless of age). The second: each Roth conversion has its own 5-year clock for penalty-free withdrawal of the converted principal before age 59½. After age 59½, both rules become largely irrelevant — you can withdraw converted funds immediately without penalty, and earnings are tax-free once your Roth IRA is at least 5 years old. If you are close to or past 59½, the 5-year rule on conversions has little practical impact.

For informational purposes only. This calculator uses simplified tax estimates based on marginal rates and does not account for state income taxes, Alternative Minimum Tax, Social Security taxation, Medicare IRMAA surcharges, or other factors that may affect your tax liability. Consult a qualified financial advisor or CPA before making Roth conversion decisions.

Sources: IRS Publication 590-A & 590-B (Contributions and Distributions for IRAs), SECURE 2.0 Act of 2022 (mandatory Roth catch-up provisions effective 2026), IRS Notice 2023-75 (SECURE 2.0 implementation guidance), IRS Rev. Proc. 2025-XX (2026 contribution limits).

Frequently Asked Questions

When does a Roth conversion make sense?
A Roth conversion makes sense when your current marginal tax rate is lower than your expected tax rate in retirement. It also makes sense when you have funds available to pay the conversion tax without touching the IRA itself, when you have a long time horizon for tax-free growth, or when you expect large required minimum distributions (RMDs) later. Converting in a low-income year — such as after retirement but before Social Security starts — is often an ideal window.
What is the SECURE 2.0 mandatory Roth catch-up rule?
Starting January 1, 2026, employees age 50 or older who earned more than $145,000 in FICA wages from their employer in the prior year must make 401(k), 403(b), and governmental 457(b) catch-up contributions as Roth contributions (after-tax) rather than pre-tax. This applies regardless of the employee's preference. Employees who earned $145,000 or less can still choose pre-tax catch-up contributions.
What is a backdoor Roth IRA and who needs it?
A backdoor Roth IRA is a two-step strategy for high earners who exceed the Roth IRA income limits ($165,000 single, $246,000 married filing jointly in 2026). Step 1: Make a non-deductible contribution to a traditional IRA ($7,000, or $8,000 if 50+). Step 2: Convert the traditional IRA to a Roth IRA. Since the contribution was after-tax, only the earnings (usually minimal if converted quickly) are taxable. There is no income limit on Roth conversions.
What is the pro-rata rule and how does it affect backdoor Roth conversions?
The pro-rata rule applies when you have pre-tax money in any traditional IRA. When you convert, the IRS treats all your IRAs as one pool and taxes conversions proportionally based on the pre-tax vs after-tax ratio. For example, if you have $90,000 in pre-tax IRA funds and make a $10,000 non-deductible contribution, only 10% of any conversion is tax-free. To avoid the pro-rata rule, consider rolling pre-tax IRA funds into your employer's 401(k) before doing a backdoor Roth.
What are the Roth IRA contribution limits and income limits for 2026?
For 2026, the Roth IRA contribution limit is $7,000 ($8,000 if age 50 or older). The income phase-out range for direct Roth IRA contributions is approximately $150,000–$165,000 for single filers and $236,000–$246,000 for married filing jointly. If your income exceeds these limits, you cannot contribute directly to a Roth IRA, but can use the backdoor Roth strategy instead.
What is the 5-year rule for Roth conversions?
Each Roth conversion starts its own 5-year clock. To withdraw converted funds (the principal) tax and penalty free before age 59½, the conversion must have been made at least 5 years ago. After age 59½, this restriction doesn't apply — you can withdraw any converted funds immediately without penalty. The 5-year rule on Roth IRA earnings (to be tax-free) is separate: your first Roth IRA must be at least 5 years old.

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