How to use this calculator
- Choose the tax year of the conversion, your filing status and your age at the end of that year. Your age decides the 65-and-over deductions, whether Medicare premiums two years later are counted, whether withholding before 59½ costs extra, and when required minimum distributions start.
- Enter your other income for the year, before deductions, and any Social Security benefits. Leave the conversion out; the calculator adds it. If anyone on your return has Marketplace health insurance, turn that on and enter the premiums from Form 1095-A.
- Enter the amount to convert and where the tax will come from. Then look at three things: the tax it adds now, how much more you could convert before the next step, and the break-even rate. Each "how much more" line has a button that sets the amount to that step.
- Set the tax rate you expect on this money if it stays in the traditional IRA, and the age at which to compare. Under More options, add qualified dividends and gains, investment income, after-tax basis for the pro-rata rule, a state rate, and a tax on savings growth.
- To plan several years, choose "Plan several years" at the top. Enter your traditional IRA balance, your other income and your Social Security in today's dollars, and pick a target, such as the top of the 12% bracket. The first year is priced exactly; later years are estimates, marked with ≈. Compare the strategies under "Compare other ways to convert". Retiring before 60? The "Before 59½" chart and "Show when you can spend it" show when each year's conversion clears its five years.
How it's calculated
The calculator figures your 2026 federal return twice, once without the conversion and once with it, and the difference is the tax the conversion adds. Each return follows Form 1040's order: the taxable part of Social Security from the IRS worksheet, adjusted gross income, the standard or itemized deduction, the senior deduction for anyone 65 or older (from 2025 through 2028, shrinking by 6% of income over $75,000, or $150,000 on a joint return), taxable income, and the tax from the IRS Tax Table below $100,000 and the rate schedule above it, with qualified dividends and long-term gains taxed at their own rates on top. The 3.8% net investment income tax is added when income passes its line.
An example
Say you are single and 63, with $40,000 of other income in 2026. Your taxable income is $23,900 and your tax $2,623. Converting $50,000 raises taxable income to $73,900 and the tax to $10,976, so the conversion adds $8,353, 16.7% of the amount. It crosses from the 12% bracket into 22%, and you could convert $31,800 more before 24%. You turn 65 in 2028, so the calculator checks IRMAA for that year: your income would be $90,000, $19,000 below the first threshold at 2026's brackets.
Social Security changes the picture. A married couple, both 67, with $48,000 of benefits and $30,000 of other income pays no federal income tax. Converting $40,000 makes $26,300 more of their benefits taxable as well, so their taxable income rises by more than the conversion and the tax is $7,103, 17.8% of the amount, although their bracket is only 12%.
The premium tax credit
For Marketplace coverage, the calculator figures the premium tax credit on each return as Form 8962 does: household income (adjusted gross income plus tax-exempt interest and the untaxed part of Social Security) as a percentage of the poverty line, the share of income you are expected to pay toward the benchmark plan at that percentage, and the credit as the rest of the benchmark premium, up to what your plan costs. The credit lost is part of the conversion's cost. In 2026 a household above 400% of the poverty line gets no credit, so a conversion that crosses that line costs the whole credit at once: for one person, $62,600 of household income.
Paying the tax, and the pro-rata rule
If the tax is withheld from the conversion, the withheld part is a withdrawal, not a conversion. Before 59½ its taxable part also carries the 10% additional tax, so the calculator withholds enough to cover the tax and that 10% together: at 45, converting $30,000 means withholding $1,581, of which $158 is the 10% tax. If the tax is more than the conversion, nothing reaches the Roth and the rest is owed from savings. With after-tax basis, Form 8606 divides your basis by the value of your traditional IRAs at year end plus this year's other withdrawals and the amount converted, rounds to three decimals, and that share of each withdrawal is tax-free, never more than your basis.
Converting vs not
The comparison follows two households that differ only by this conversion. One has the Roth. The other keeps the money in the traditional IRA, takes its required minimum distributions from your RMD age by the IRS Uniform Lifetime Table, pays your future tax rate on them and saves the rest, and keeps in savings the tax it did not pay and any IRMAA it avoided. Both grow at the same return, and at the compare age the traditional IRA is valued after tax at your future rate. The break-even rate is the future rate at which the two come out the same. With the tax paid from savings and no tax on savings growth, it equals the tax now as a share of the conversion: 16.7% in the example, where the 22% you entered leaves the converting household $23,069 ahead at 95.
Planning several years
The plan view repeats that calculation for every year from 2026 until the year before required minimum distributions start, on two households: one converts each year as much as fits below your target, the other never converts. Each year is priced on its own return, with and without that year's conversion, so Social Security, the senior deduction, IRMAA two years later and the premium tax credit all move the amount and its cost. You can also stop each year before the next IRMAA step or the 400% line of the credit, and the table says which limit set each year's amount. In the example, filling the 12% bracket converts $26,500 in 2026 for $3,183 of tax, and about $150,000 through 2037.
Years after 2026 use today's tax law with its dollar amounts rising at your inflation rate, and IRMAA thresholds indexed the way the law indexes them; they are estimates, rounded on the page. A setting under More options raises every bracket's rate from a year you choose. After the last conversion, what is left in the traditional IRA, its required minimum distributions and your withdrawals are taxed at the rate you enter, and the break-even rate is the one at which the two households come out the same. It can differ from the plan's tax per converted dollar, because money converted early grows longer: the break-even weighs each year's cost by that growth.
When you can spend converted money
Each conversion starts its own five-year period on January 1 of the year you convert. Taking out converted money before its five years end and before 59½ carries the 10% additional tax on it, although its income tax was paid when you converted. Withdrawals come out of regular contributions first and then conversions oldest first, so every conversion that has cleared comes out before any that has not. For each year you are 59 or younger at its end, the plan view adds up what you converted, after any tax withheld from it, and shows how much has cleared. For a single 45-year-old with no other income filling the 12% bracket, $66,500 converted in 2026 clears in 2031, and about $745,000 has cleared by 2040, less anything taken out. The 10% ends at 59½, which falls in the year you turn 59 or the first half of the year you turn 60, depending on your birthday; a conversion that clears later than that shows "59½ first".
Assumptions and limits
- Federal tax on the 2025 or 2026 return you choose, with no Schedule 1 adjustments, no credits other than the premium tax credit, and no alternative minimum tax. Your other income is held as you enter it, and so are itemized deductions, although a conversion can change some of them (medical expenses above 7.5% of income, the state and local tax limit).
- State tax is one flat rate on the taxable part of the conversion; state rules on retirement income are not modeled.
- With after-tax basis, the pro-rata share uses your year-end IRA value and the other withdrawals you enter. The conversion's tax-free share is figured on the whole amount, which can differ from Form 8606's two lines by a cent.
- IRMAA uses 2026's brackets and premiums for 2028, whose figures are not published yet, and counts a full year of premiums for anyone 65 or older by the end of 2028, which overstates the first year for anyone who turns 65 during it. The brackets are indexed to inflation, so the real 2028 line will likely be higher; the premiums rise too, so a surcharge that does apply will likely be larger.
- The comparison uses one return for the Roth, the traditional IRA and savings, and the future tax rate you enter for money left in the traditional IRA. It assumes the Roth money stays invested until the compare age. By default no tax is taken from savings growth, which leaves out an advantage of converting: with 10% taken each year, the example's break-even rate falls from 16.7% to 9.1%.
- In the one-year view, the 10% additional tax is priced only on tax withheld before 59½; the plan view also charges it on withdrawals you live on before 59½. Exceptions such as disability are not modeled.
- The premium tax credit assumes coverage for all 12 months and the poverty line for the 48 contiguous states and DC, and counts the whole credit lost as a cost. For 2025, the repayment of advance credit can be capped, so what you repay may be less.
- In the plan view, years after 2026 are estimates: today's law with its dollar amounts rising at your inflation rate, one rate standing in for the several price indexes the law uses. Amounts the law fixes stay fixed (Social Security's taxation thresholds, the 3.8% tax's thresholds, the senior deduction until it ends after 2028). IRMAA thresholds are indexed as the law does and premiums rise at your inflation rate, so the plan's first IRMAA figures can differ from the one-year view's, which uses 2026's published figures. The estimates keep the law's amounts exact to the cent where the IRS rounds down to $25 or $50, hold IRMAA's top threshold until 2028 as the law does, and hold the premium tax credit's percentages at the newest year published. Part B's standard premium rose faster than inflation from 2025 to 2026 ($185.00 to $202.90), so the estimated surcharges are more likely too low than too high.
- Social Security and a pension count for the whole year from the age they start. Tax withheld from a conversion is treated as before 59½ in a year you are 59 or younger at its end and after it from 60, where the one-year view asks. Withdrawals you live on that outlast the IRA come from savings before 60 and from the money converted to the Roth IRA from 60, which avoids the 10% on converted money taken out within five years.
- "When you can spend it" counts only the conversions in the plan, after any tax withheld from them, and the plan's own figures assume nothing comes out of the Roth IRA before 60; what has cleared is a running total, less anything you take out. Regular Roth IRA contributions come out first and are always free of tax and the 10%; conversions made before the plan come out before these ones; neither is asked, so with either, more is available sooner than shown. Growth on converted money comes out last: before 59½ it is taxed and carries the 10%, and after 59½ it is tax-free once five years have passed since your first Roth IRA contribution or conversion. The view runs to the year you turn 59. With a birthday in July or later you reach 59½ in the first half of the year you turn 60, and until then converted money still inside its five years carries the 10%. Exceptions to the 10% such as disability or a series of equal payments are not modeled.
- After the last conversion, the plan models no IRMAA or premium tax credit beyond that conversion's IRMAA year. That leans toward not converting, since the larger IRA's larger required minimum distributions are the likelier to raise Medicare premiums.
- The plan holds your filing status and household every year (a qualifying surviving spouse moves to head of household after two years) and assumes a couple both live through it. Social Security rises with your inflation rate and a pension does not; Marketplace premiums rise with inflation, although they also rise with age. It converts only your own traditional IRAs, treats them as all pretax, stops the year before required minimum distributions start, and assumes the tax can be paid from savings unless you choose the conversion.
- It does not model your heirs' own brackets or the 10-year rule for inherited IRAs, conversions after required minimum distributions start, after-tax basis in the plan, a spouse's IRA, Roth conversions inside a 401(k) plan, estimated tax payments, blindness, or an IRMAA appeal after a life-changing event.
Input field details
What to enter in each box, where to find the number, and how this calculator treats it. When two calculators give different answers from the same numbers, it's usually because they handle one of these differently.
Filing status
The status you will file under for the year of the conversion.
Where to find itThe filing status box at the top of Form 1040.
How this tool treats itIt sets the brackets, the standard deduction, how much of your Social Security is taxable and which IRMAA table applies. If you are married and file separately, say whether you lived with your spouse at any time in the year: if you did, up to 85% of your Social Security is taxable from the first dollar, and Medicare uses its strictest table.
Age at the end of the year
Your age on December 31 of the conversion year, and your spouse’s on a joint return.
How this tool treats itAt 65 you get a larger standard deduction and, from 2025 through 2028, the senior deduction. Your age also sets whether Medicare premiums two years later are counted, whether a withdrawal before 59½ applies, and the age your required minimum distributions start (73 if you were born from 1951 through 1959, 75 if born in 1960 or later). The IRA being converted is yours. The IRS counts someone born on January 1 as 65 a year early for the standard deduction; the calculator uses the age you enter, so that reader sees a slightly higher tax.
Allowed range18 to 98 (your spouse, 18 to 110)
Other income this year, before deductions
Everything taxed as ordinary income this year apart from the conversion and Social Security, before any deduction: wages, pensions, IRA and 401(k) withdrawals, interest, nonqualified dividends, short-term gains, rental and business income.
Where to find itLast year’s return is a good start: Form 1040 lines 1z, 2b, 3b (the part that is not qualified), 4b, 5b and 8.
How this tool treats itInclude any required minimum distribution you must take this year. That part of your IRA cannot be converted.
Allowed range$0 to $10,000,000
Social Security benefits
The Social Security benefits you receive this year, before Medicare premiums are taken out. On a joint return, both of you together.
Where to find itBox 5 of Form SSA-1099.
How this tool treats itUp to 85% of benefits can be taxable, depending on your other income. A conversion raises that income, so it can make more of your benefits taxable, which is why the tax on a conversion can run above your bracket.
Allowed range$0 to $250,000
Amount to convert
The total you will move out of your traditional IRA this year, including any tax withheld from it.
Where to find itYour plan: the amount you will ask your IRA custodian to convert.
How this tool treats itAll of it is taxable unless you have after-tax basis in your traditional IRAs (More options). You cannot undo a conversion made after 2017.
Allowed range$0 to $10,000,000
Pay the tax from
Where the money for the tax comes from: your savings outside the IRA, or tax withheld from the conversion.
How this tool treats itTax withheld from the conversion never reaches the Roth IRA: it is a withdrawal. Before 59½, the taxable part of a withdrawal carries a 10% additional tax, which also has to come out, so more is withheld. At 59 or 60 the calculator asks whether you will be 59½ when the tax is withheld.
Tax rate on this money if you don’t convert
The rate, federal and state together, you expect this money to be taxed at when it comes out of the traditional IRA later, whether you take it or your heirs do.
How this tool treats itIt is a guess about the future, so the calculator also works out the break-even rate, the rate at which converting and not converting come out the same. It is applied to every required minimum distribution and to what is left at the compare age.
Allowed range0% to 60%
Compare at age
The age at which to compare the two choices, after tax.
How this tool treats itThe default is 95, the planning age the calculators on this site use. It must be at least two years away, so the Medicare premium a conversion affects falls inside the comparison.
Allowed rangeyour age + 2 to 100
Qualified dividends and net long-term gains
Your qualified dividends plus your net long-term capital gain after any short-term losses. Short-term gains go in other income; a net capital loss is not modeled.
Where to find itForm 1040 line 3a, plus the smaller of Schedule D lines 15 and 16 when both are gains (line 4 of the Qualified Dividends and Capital Gain Tax Worksheet).
How this tool treats itThey are taxed at 0%, 15% or 20% on top of your ordinary income, so a conversion can push some of them from 0% to 15%. The calculator counts that as part of the conversion’s cost.
Allowed range$0 to $10,000,000
Investment income included in other taxable income
The interest, ordinary dividends, rents and royalties inside your other taxable income.
How this tool treats itUsed only for the 3.8% net investment income tax, which falls on the smaller of your investment income (this plus your qualified dividends and gains) and your income over $200,000 ($250,000 on a joint return, $125,000 separately). The conversion is not investment income, but it can push you over the line.
Allowed range$0 to $10,000,000
Tax-exempt interest
Interest that is not taxed, such as municipal bond interest.
Where to find itForm 1040 line 2a.
How this tool treats itIt counts toward how much of your Social Security is taxable and toward the income Medicare uses for IRMAA.
Allowed range$0 to $10,000,000
Itemized deductions
Your total itemized deductions, if you itemize. Leave it at 0 to use the standard deduction.
Where to find itSchedule A, line 17.
How this tool treats itThe larger of this and your standard deduction is used, and it is held the same with and without the conversion.
Allowed range$0 to $10,000,000
After-tax basis in your traditional IRAs
Your after-tax basis: nondeductible contributions to your own traditional IRAs not yet taken out. Then the value of all your traditional, SEP and SIMPLE IRAs on December 31 of the conversion year, after the conversion (not Roth IRAs, inherited IRAs, or your spouse’s), and any other withdrawals from them this year, including a required minimum distribution.
Where to find itLine 14 of your last Form 8606, plus nondeductible contributions for this year made by December 31; the year-end value from your December statements.
How this tool treats itThe pro-rata rule treats all your traditional IRAs as one: each dollar that comes out, converted or not, carries the same share of basis, basis ÷ (year-end value + other withdrawals + the amount converted), rounded to three decimals as Form 8606 line 10 allows, and never more than your basis in total. Other withdrawals are part of your other income; the calculator takes their tax-free share off it. A year-end value of 0 means the whole IRA is converted.
Allowed range$0 to $10,000,000 (value, $0 to $50,000,000)
State income tax rate on the conversion
Your state’s tax rate on the conversion, as one flat percentage. Leave it at 0 if your state does not tax it.
How this tool treats itApplied to the taxable part of the conversion. State rules on retirement income vary; the calculator does not model them.
Allowed range0% to 15%
Investment return
The yearly return you expect, before inflation.
How this tool treats itThe same return is used for the Roth IRA, the traditional IRA and your savings, so the comparison turns on tax alone. The default is 7%.
Allowed range0% to 20%
Tax on savings growth
The share of each year’s growth in your savings that you expect to lose to tax.
How this tool treats itIf you pay the conversion tax from savings, that money no longer grows in savings, where its growth would be taxed; in the Roth, the same growth is tax-free. The default of 0% leaves that advantage out, which is the reading least favorable to converting. About 5% to 15% describes a taxable fund whose dividends and gains are taxed each year.
Allowed range0% to 50%
Inflation
The yearly inflation to use when you show the comparison in today’s dollars.
How this tool treats itIt changes only how the dollar amounts are shown, never the break-even rate. The default is 2.5%.
Allowed range0% to 10%
Count Medicare drug coverage
Leave on if you, or anyone counted, will have a Medicare Part D plan or a Medicare Advantage plan with drug coverage two years from now. Turn off if your drug coverage will come from VA, TRICARE or an employer’s retiree plan instead.
How this tool treats itIRMAA adds a surcharge to Part B and, for anyone enrolled in a Medicare drug plan, to Part D (20 CFR 418.2010(b)(8)). VA, TRICARE and employer drug coverage that is not a Medicare plan carry no Part D surcharge.
Year of your first Roth IRA contribution or conversion
The tax year FOR which you first put money into any Roth IRA (a contribution made in April 2024 for 2023 counts as 2023). Leave it at 0 if this conversion opens your first one.
How this tool treats itEarnings in a Roth IRA come out tax-free once five tax years have passed since that year and you are 59½. Each conversion also has its own five-year period for the 10% additional tax, which matters only before 59½.
Allowed range1998 to the conversion year
One year or several years
One year prices a single conversion on this year’s return. Plan several years works out how much to convert each year until your required minimum distributions start.
How this tool treats itThe plan prices each year on that year’s whole federal return with and without the conversion. Years after the newest one the IRS has published use today’s law with its dollar amounts rising at your inflation rate, and are marked as estimates.
Your traditional IRA balance at the end of last year
The total of your own traditional, SEP and SIMPLE IRAs on December 31 of last year. Not Roth IRAs, inherited IRAs or your spouse’s.
Where to find itYour December statements, or box 5 of Form 5498 (fair market value of the account).
How this tool treats itIt grows at your investment return. Each year your withdrawals to live on come out first, and the conversion comes from what is left. The plan treats the whole balance as pretax.
Allowed range$0 to $10,000,000
Other income stops after age
The last age at which your other income, such as wages, continues. Leave it at 0 if it continues every year.
How this tool treats itAfter that age all of your other income stops, including any investment income counted in it. Until then it rises each year at your inflation rate.
Allowed range0 (never) to 100
Social Security, in today’s dollars, and the age it starts
The yearly benefit your Social Security statement shows for the age you plan to start, and that age. On a joint return, add your spouse’s under More options. Already receiving benefits? Enter your current yearly amount and an age at or below your age now.
Where to find itYour Social Security statement in your my Social Security account at ssa.gov. It shows monthly amounts: multiply by 12.
How this tool treats itA benefit counts for the whole year from the age it starts and rises each year at your inflation rate. Up to 85% of it can be taxable, and a conversion can make more of it taxable.
Allowed range$0 to $100,000 a year each, starting at 18 to 70
Pension or annuity, per year, and the age it starts
The yearly taxable amount of a pension or annuity, and the age it starts.
Where to find itYour plan’s benefit estimate; once it is paid, box 2a of Form 1099-R.
How this tool treats itThe same dollar amount every year from that age, taxed as ordinary income. A cost-of-living increase is not modelled.
Allowed range$0 to $1,000,000, starting at 18 to 100
Withdrawals from this IRA to live on, each year
What you take out of these IRAs each year to spend, in today’s dollars, apart from the conversions.
How this tool treats itEach year the withdrawal comes out before the conversion and is taxed as income, both with the plan and with no conversions. It rises at your inflation rate and continues after the last conversion, where it counts toward each required minimum distribution. Before 59½ it carries the 10% additional tax. If the IRA runs out, the plan pays the withdrawals from savings before 60, and from the money converted to the Roth IRA from 60.
Allowed range$0 to $1,000,000
Each year, convert
The top of a tax bracket to fill each year, or a set amount to convert each year.
How this tool treats itFor a bracket, the calculator finds the largest whole-dollar conversion that keeps your ordinary taxable income within it, on that year’s return with your other income, Social Security and deductions. With those limits turned on, it stops sooner at the next IRMAA step or at 400% of the poverty line, and each year shows which limit set its amount. A set amount is converted as entered, up to what is in the IRA, and those limits do not apply to it.
Allowed rangea set amount of $0 to $10,000,000
Last year to convert
The last calendar year you want to convert. Leave it at 0 to convert every year until the year before your required minimum distributions start.
How this tool treats itThe plan covers at most 30 years. A year before the first year reads as the first year, and a year at or after the start of your required minimum distributions reads as the year before it.
Stop before the next IRMAA step
Turn on to keep each year’s conversion below the income that would move your Medicare premiums two years later up to the next IRMAA step.
How this tool treats itMedicare reads the return from two years earlier, so the limit applies from the year you, or your spouse on a joint return, turn 63. Thresholds for years not yet published are estimated the way the law indexes them, at your inflation rate. It applies to a bracket target, not to a set amount.
Stop at the 400% line
With Marketplace coverage turned on, keep each year’s conversion from taking household income above 400% of the poverty line, where the premium tax credit ends.
How this tool treats itIt applies in a year with that limit (from 2026), when your household income without the conversion is at or below the line. Income exactly at 400% still gets the credit. It applies to a bracket target, not to a set amount.
If tax rates rise
How many percentage points higher every bracket’s rate might be, and the year the change starts. Leave the points at 0 for today’s law.
How this tool treats itIt raises every bracket’s rate by the same number of points in the years you convert, from the year you choose; the bracket tops, the deductions and the capital-gains rates stay as they are. It does not change the tax rate after the plan: raise that too if you expect the change to last. A starting year of 0 means four years after the first year.
Allowed range0 to 10 points
Questions
How is a Roth conversion taxed?
How much should I convert this year?
How much should I convert each year?
Should I fill the 12% or the 22% bracket?
Does a Roth conversion affect Medicare premiums?
Does a Roth conversion reduce the ACA premium tax credit?
Should I pay the tax on a conversion from the IRA itself?
What is the five-year rule for Roth conversions?
Can I undo a Roth conversion?
What if I have after-tax money in my traditional IRA?
When does a Roth conversion pay off?
Version history
- October 8, 2026 (version 2.1.0): The plan view now shows, for each year before 59½, what you converted, the year it clears its five years and how much converted money you could take out without tax or the 10%. Other results are unchanged.
- October 2, 2026 (version 2.0.1): The largest IRA balance the plan accepts is now $10,000,000, down from $20,000,000, because larger balances could stop the plan with an error at extreme returns. Results below $10,000,000 are unchanged.
- September 29, 2026 (version 2.0.0): A plan view: how much to convert each year until RMDs start, each year priced on its own return, with the limit that sets each amount, strategies side by side and a break-even rate. One-year results are unchanged.
- September 28, 2026 (version 1.0.0): First version: the tax a conversion adds on your 2025 or 2026 return, with Social Security, the senior deduction, the 3.8% tax, the premium tax credit, IRMAA, the pro-rata rule and a break-even rate.