Finance calculators

Roth Conversion Calculator

Updated Nov 9, 2026 By Infinity Calculator Formulas Sources
3.0 · Rate
Account Information
$
$
Personal & Timeline
%
Tax Information
The year you convert. Sets the federal brackets the optimizer fills.
$
%
Some states exempt retirement income.
%
Taxable Side Account
%
Qualified dividends and long-term gains are taxed at 0%, 15% or 20%. Add your state's rate, and 3.8% if the net investment income tax applies: modified AGI over $200,000 single or head of household, $250,000 married filing jointly, $125,000 married filing separately.
%
Used from your retirement age, and on the sale. Build it the same way from your retirement income and state.
%
Part of the annual return, not added to it. The S&P 500's yield in June 2026 was 1.10%.
Estimated change in net worth at retirement
$0.00
Keep Traditional IRA
Balance at retirement$0.00
Est. tax on withdrawal$0.00
Side account (tax savings invested)$0.00
Est. tax on side account gains$0.00
Net after-tax value$0.00
Roth Conversion
Roth balance at retirement (tax-free)$0.00
Taxes paid today on conversion$0.00
Net after-tax value$0.00
Conversion Tax Cost
Break-Even Analysis
Pay Taxes Now vs. Later
Effective rate if you convert now0.0%
Effective rate on Traditional withdrawals later0.0%
Bracket-Fill Optimizer
Net After-Tax Value Over Time
Step-by-Step Solution

Introduction

A Roth conversion moves money from a traditional retirement account, like a Traditional IRA or 401(k), into a Roth IRA. You pay taxes on the money now, but it then grows tax-free and comes out tax-free in retirement. The big question is: does paying taxes today save you more money in the long run?

This Roth Conversion Calculator helps you answer that question. Enter your account balance, conversion amount, age, tax rates, and expected investment return. The calculator compares two paths side by side: keeping your money in the traditional account versus converting to a Roth. It shows you which option could leave you with more money at retirement, how long it takes the Roth to break even, and how much you would owe in taxes if you convert today. You can also convert the same amount each year for several years and compare the whole plan.

You can also turn on advanced options to account for Required Minimum Distributions (RMDs), adjust results for inflation, and check whether the conversion could trigger Medicare IRMAA surcharges. A bracket-fill optimizer tells you how much you can convert without jumping into a higher federal tax bracket. All results update instantly with a year-by-year chart, data table, and full step-by-step math breakdown.

How to Use Our Roth Conversion Calculator

Enter details about your retirement account, age, and tax rates below. The calculator will show whether converting to a Roth IRA helps or hurts your net worth at retirement, how much tax you will owe today, and when the conversion breaks even.

Current Account Balance: Enter the total dollar amount currently in your retirement account.

Conversion Amount per Year: Enter how much of the balance you want to move into a Roth IRA in each conversion year. Check the "Convert full balance" box to convert everything. With one year of conversions that is the whole balance. Over several years it is the same amount each year that empties the account by the last conversion, growing at your annual return in between.

Years of Conversions: Enter how many years in a row you convert that amount, starting this year. Enter 1 for a single conversion. The conversions must end before your retirement age, and the calculator tells you if the balance would run out first and the most it can support each year.

Current Age: Enter your age today. You must be between 18 and 80.

Retirement Age: Enter the age you plan to retire. This must be older than your current age, up to 100.

Annual Return: Enter the average yearly growth rate you expect on your investments. The default is 7%. This rate applies to both the Roth and Traditional scenarios equally.

Tax Year: Pick the year you convert, 2026 or 2027. This sets the federal brackets the optimizer fills. The 2027 brackets come from Revenue Procedure 2026-35.11

Filing Status: Choose Single or Married Filing Jointly. This affects the tax bracket optimizer and IRMAA thresholds.

Current Taxable Income: Enter your taxable income this year, not counting the conversion itself. The calculator uses this to check which tax bracket you are in and how much room you have before the next bracket.

Current Federal Marginal Rate: Select the federal tax bracket that applies to you right now. This is the rate you will pay on the converted amount today.

Expected Federal Rate in Retirement: Select the federal tax bracket you expect to be in when you retire. A lower future rate favors keeping the Traditional IRA. A higher future rate favors converting to Roth.

Current State Tax Rate: Enter your state income tax rate today. If your state has no income tax, enter 0.

Expected State Rate in Retirement: Enter the state tax rate you expect to pay in retirement. If you plan to move to a no-tax state, enter 0.

Dividend Yield: Enter the yearly dividend yield of what you would hold in the side account. It is part of your annual return, not added to it. The default is the S&P Composite index's latest published yield in Robert Shiller's stock market data, its dividends over the past twelve months divided by its price.8 In June 2026 that was 1.10%.

Current Dividend & Gains Tax Rate: Enter your tax rate on qualified dividends and long-term capital gains, plus your state's rate. Qualified dividends are taxed at the lower capital gain rates.9 The side account pays this rate on its dividends each year before your retirement age. The default of 15% is the long-term capital gains rate for most people.7 Add 3.8% if the net investment income tax applies to you: it applies when your modified adjusted gross income is over $200,000 if you are single or head of household, $250,000 if you are married filing jointly, or $125,000 if you are married filing separately.10

Expected Dividend & Gains Rate in Retirement: Enter the rate you expect to pay on qualified dividends and long-term capital gains in retirement, plus your state's rate then, and 3.8% if the net investment income tax will still apply. The side account pays this rate on its dividends each year from your retirement age on, and on its growth above the cost basis when it is counted as sold at your retirement age. The default is 15%.

Account for RMDs: Turn this on under Advanced Options to include Required Minimum Distributions. Traditional IRAs force you to withdraw money starting at age 73, which raises your taxable income.1 Roth IRAs have no RMDs.

Adjust for Inflation: Turn this on to show all future values in today's dollars using a 2.5% inflation rate. This makes it easier to understand what your money will actually be worth.

Medicare IRMAA Awareness Flag: Turn this on to check whether your income plus the conversion amount could trigger higher Medicare premiums. The calculator will flag which IRMAA surcharge tier you may hit, based on your Modified Adjusted Gross Income, which is what Medicare uses for IRMAA thresholds.

Click Calculate to see your results. Click Reset to return all fields to their default values.

What Is a Roth Conversion?

A Roth conversion is when you move money from a traditional retirement account, like a Traditional IRA or 401(k), into a Roth IRA. When you do this, you pay income taxes on the amount you move now instead of paying taxes later when you withdraw the money in retirement.

Why Would You Convert to a Roth IRA?

The main reason people convert is to save money on taxes over time. If you expect your tax rate to be higher in retirement than it is today, paying taxes now at the lower rate can leave you with more money later. Once the money is in a Roth IRA, it grows tax-free thanks to compound interest, and you pay zero taxes when you take it out in retirement. Roth IRAs also have no required minimum distributions (RMDs), so you are never forced to withdraw money at a certain age.2

When Does a Roth Conversion Make Sense?

A Roth conversion tends to work best when:

  • Your current effective tax rate is lower than what you expect to pay in retirement.
  • You have enough cash outside your retirement accounts to pay the tax bill.
  • You have many years until retirement, giving the converted money more time to grow tax-free.
  • You want to reduce future RMDs that would start at age 73.1

It may not make sense if your tax rate will drop significantly in retirement, or if you need to pull money from the converted account itself to cover the taxes.

How This Calculator Works

This Roth conversion calculator compares two paths side by side. In Scenario A, you keep your money in the traditional account, let it grow, and pay taxes when you withdraw in retirement. In Scenario B, you convert to a Roth IRA, pay taxes today, and let the money grow tax-free. The calculator accounts for federal and state taxes, investment growth, and the opportunity cost of paying taxes now. In Scenario A, the money you would have paid in conversion tax stays invested in a taxable side account, so both paths cost you the same out of pocket. That money was already taxed, so only what it earns is taxed: its dividends each year, at your current dividend and gains tax rate before your retirement age and at your retirement one from it, and its price growth once, at the retirement rate, when it is sold at retirement. The calculator counts the side account at what it would leave you if you sold it. It then shows you which option is estimated to leave you with more money at retirement and how long it takes the Roth conversion to break even.

Key Terms to Know

  • Marginal Tax Rate – The tax percentage you pay on your last dollar of income. This is the rate applied to the converted amount.
  • Break-Even Point – The age at which the Roth conversion starts to beat keeping the traditional account.
  • RMDs (Required Minimum Distributions) – Mandatory yearly withdrawals from traditional retirement accounts that begin at age 73.1 Roth IRAs do not have RMDs.
  • IRMAA – Income-Related Monthly Adjustment Amount. A surcharge added to Medicare premiums when your income exceeds certain thresholds. A large conversion can push you above these limits.
  • Bracket-Fill Strategy – Converting just enough each year to fill your current tax bracket without jumping into a higher one. This spreads the tax cost over several years.

Formulas used

Conversion Tax Cost (paid in each conversion year)
T = C \times t_{now} \quad \text{where } t_{now} = t_{fed} + t_{state}
Roth Balance at Retirement (tax-free)
B_{Roth} = \sum_{k=0}^{Y-1} C \times (1 + r)^{n-k}
Traditional IRA Balance at Retirement
V_{Trad} = \sum_{k=0}^{Y-1} C \times (1 + r)^{n-k}
Side Account at Retirement (tax savings invested)
V_{side} = \sum_{k=0}^{Y-1} T \times q_{now}^{\,n-1-k} \times q_{ret},\qquad q_{now} = 1 + r - d g_{now},\quad q_{ret} = 1 + r - d g_{ret}
Side Account Cost Basis at Retirement
\text{Basis} = \sum_{k=0}^{Y-1} \left[T + d(1 - g_{now})\,T\,\frac{q_{now}^{\,n-1-k} - 1}{r - d g_{now}} + d(1 - g_{ret})\,T\,q_{now}^{\,n-1-k}\right]
Net After-Tax Value, Keep Traditional
A = V_{Trad} \times (1 - t_{ret}) + V_{side} - g_{ret} \times \max(0,\ V_{side} - \text{Basis})
Net Worth Difference (Roth minus Traditional)
\Delta = B_{Roth} - A
Inflation Adjustment to Today's Dollars
\text{Real Value} = \frac{\text{Nominal Value}}{(1.025)^{n}}
Required Minimum Distribution (age ≥ 73) 1
RMD = \frac{V_{Trad}}{\text{Life Expectancy Factor}}
Traditional IRA Balance With RMDs (each age a from 73)
V_{Trad,a} = V_{Trad,a-1} \times (1 + r) - \text{RMD}_a,\qquad \text{RMD}_a = \frac{V_{Trad,a-1} \times (1 + r)}{\text{Life Expectancy Factor}_a}
Part of Each RMD Kept After Its Tax
\text{Kept}_a = \text{RMD}_a \times (1 - t_a),\qquad t_a = t_{now}\text{ before your retirement age, }t_{ret}\text{ from it}
Side Account and Cost Basis With RMDs
V_{side,a} = V_{side,a-1} \times (1 + r - d g_a) + \text{Kept}_a,\qquad \text{Basis}_a = \text{Basis}_{a-1} + d(1 - g_a)\,V_{side,a-1} + \text{Kept}_a,\qquad g_a = g_{now}\text{ before your retirement age, }g_{ret}\text{ from it}

Frequently asked questions

How much tax will I pay on a Roth conversion?

The converted amount is added to your taxable income for the year. You pay federal income tax at your marginal rate plus any state income tax. For example, if you convert $100,000 and your combined federal and state rate is 29%, you would owe about $29,000 in taxes. The calculator shows your exact federal and state tax amounts in the Conversion Tax Cost section. If you convert over several years, it shows the tax for each year and the total for all of them.

Should I pay the conversion tax from the converted funds or from outside money?

Always pay the tax from outside money if you can. If you pull the tax payment from the converted amount, you lose that money's future tax-free growth. You may also owe a 10% early withdrawal penalty if you are under age 59½.3 This calculator assumes you pay the tax from outside funds.

What does the break-even age mean?

The break-even age is when the Roth conversion scenario catches up to the keep-Traditional scenario in total net worth. Before that age, you would have been better off not converting. After that age, the Roth pulls ahead. A shorter break-even period means the conversion pays off faster.

Can I convert only part of my account?

Yes. You can convert any amount you want, not just the full balance. Many people convert a portion each year to stay within a lower tax bracket. This is called a bracket-fill strategy. The calculator's Bracket-Fill Optimizer tells you how much room you have in your current bracket. Enter that amount and the number of years in Years of Conversions to compare the whole plan.

Is there an income limit for Roth conversions?

No. Unlike Roth IRA contributions, there is no income limit for Roth conversions. Anyone can convert regardless of how much they earn. IRS Publication 590-A says you can convert a traditional IRA to a Roth IRA, and the conversion is treated as a rollover.5 There is also no limit on the dollar amount you can convert in a single year.

What is the side account in the Traditional IRA scenario?

When you keep the Traditional IRA, you do not pay conversion taxes today. The calculator assumes you invest that tax savings in a regular taxable account, called the side account. This makes the comparison fair because both scenarios use the same amount of out-of-pocket money. The side account earns your annual return. Its dividends are taxed each year and the rest is reinvested: at your current dividend and gains tax rate before your retirement age, and at your retirement one from it. Its price growth is taxed once, when it is sold, at the rate for that year. You have a capital gain when you sell an investment for more than its cost basis.7 The calculator shows the side account at what it would leave you if you sold it. The money you put in was already taxed, so only its growth is taxed, never the amount itself.

What is IRMAA and why does it matter for Roth conversions?

IRMAA stands for Income-Related Monthly Adjustment Amount. It is a surcharge on your Medicare Part B and Part D premiums when your income is above certain thresholds.4 Social Security uses your modified adjusted gross income for the tax year 2 years before the year the premium applies.6 So a large Roth conversion can push your income past these thresholds and raise your Medicare premiums two years later. Turn on the IRMAA Awareness Flag in Advanced Options to check this.

How do RMDs affect the Roth conversion decision?

Traditional IRAs require you to start taking withdrawals at age 73, called Required Minimum Distributions.1 These forced withdrawals increase your taxable income whether you need the money or not. Roth IRAs have no RMDs.2 Converting reduces your future Traditional IRA balance, which lowers or eliminates future RMDs. Turn on the RMD toggle in Advanced Options to see this effect. A distribution from a Traditional IRA is taxable in the year you receive it,1 so the calculator taxes each RMD at your current rate if it comes before your retirement age and at your retirement rate after that. What is left goes into the side account and adds to its cost basis in full, because it was already taxed. The step-by-step lists every RMD taken before your retirement age.

What annual return should I use?

The default is 7%, which reflects a long-term average for a diversified stock and bond portfolio before inflation. If your portfolio is more conservative, try 5% or 6%. If it is more aggressive, try 8% or 9%. The same rate is applied to both scenarios, so the return rate does not favor one over the other.

What does the inflation adjustment do?

When you turn on Adjust for Inflation, the calculator shows all future dollar amounts in today's purchasing power using a 2.5% annual inflation rate. This helps you understand what your money will actually buy in the future rather than seeing a large number that may be worth less due to rising prices.

Why does a lower future tax rate favor keeping the Traditional IRA?

With a Traditional IRA, you pay taxes when you withdraw in retirement. If your retirement tax rate is lower than your current rate, you save money by waiting to pay taxes later at the cheaper rate. Converting to a Roth means paying the higher rate now, which costs more. The calculator's Pay Taxes Now vs. Later section compares both rates visually.

What happens to the rest of my balance if I only convert part of it?

The unconverted portion stays in your Traditional IRA and continues to grow tax-deferred. This calculator only compares the portion you convert. A note will appear reminding you that the remaining balance is not included in the comparison. When you convert over several years, the note shows how much is left after the last conversion.

Is a Roth conversion the same as a Roth contribution?

No. A Roth contribution is new money you put into a Roth IRA each year, subject to annual limits and income restrictions. A Roth conversion moves existing money from a traditional retirement account into a Roth IRA. Conversions have no annual limit and no income restriction.

When is the best time of year to do a Roth conversion?

Many people convert early in the year so the money has more time to grow tax-free. Others wait until late in the year when they have a clearer picture of their total income and can fine-tune the conversion amount to stay within a tax bracket. There is no single best time. It depends on your situation.

Can I do a Roth conversion if I am already retired?

Yes. There is no age limit on Roth conversions. Retirees often convert in years when their income is lower, such as the gap between retiring and starting Social Security or RMDs. This lets them convert at a lower tax rate.

What is the bracket-fill optimizer?

The bracket-fill optimizer calculates how much room is left in your current federal tax bracket based on your taxable income. It tells you the maximum amount you can convert without pushing any of the conversion into the next higher bracket. This helps you spread conversions over several years to minimize taxes. Set Years of Conversions to see what converting that amount each year adds up to.

Sources

  1. Publication 590-B, Distributions from Individual Retirement Arrangements (IRAs). Internal Revenue Service. 2025;For use in preparing 2025 returns. Accessed September 11, 2026.
  2. Roth comparison chart. Internal Revenue Service. Accessed September 11, 2026.
  3. Topic no. 557, Additional tax on early distributions from traditional and Roth IRAs. Internal Revenue Service. Accessed September 11, 2026.
  4. Medicare Premiums: Rules For Higher-Income Beneficiaries. Social Security Administration. Accessed September 11, 2026.
  5. Publication 590-A (2025), Contributions to Individual Retirement Arrangements (IRAs). Internal Revenue Service. 2025;Chapter 2, Conversions. Accessed October 7, 2026.
  6. 20 CFR 418.1135 What modified adjusted gross income information will we use to determine your income-related monthly adjustment amount? Code of Federal Regulations. Social Security Administration. § 418.1135(a). Accessed October 7, 2026.
  7. Topic no. 409, Capital gains and losses. Internal Revenue Service. Accessed September 11, 2026.
  8. Shiller RJ. US Stock Price, Earnings and Dividends as well as Interest Rates and Cyclically Adjusted Price Earnings Ratio (CAPE) since 1871. Robert J. Shiller. 2026;ie_data.xls, Data sheet. Accessed November 2, 2026.
  9. Topic no. 404, Dividends. Internal Revenue Service. Accessed November 2, 2026.
  10. Topic no. 559, Net investment income tax. Internal Revenue Service. Accessed November 7, 2026.
  11. Revenue Procedure 2026-35. Internal Revenue Service. 2026;section 3.01. Accessed November 9, 2026.

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