Roth IRA Conversion Calculator

A Roth IRA conversion calculator estimates the tax cost of moving money out of a Traditional IRA and into a Roth IRA, then projects how both the converted and unconverted balances would grow from that point forward. The way the resulting tax bill actually gets paid changes the long term outcome of the conversion, which is why the tool treats that choice separately from the conversion amount itself. Alongside the tax estimate, the calculator shows a break-even year and a break-even tax rate, giving two different ways to judge whether the move pays off. It also helps size a conversion so the amount moved fills the available room in the current tax bracket instead of spilling into a higher one. For anyone holding a mix of pre-tax and after-tax IRA money, the calculator accounts for the pro-rata rule, which determines how much of any conversion is actually taxable. Timing matters as well, since a temporary dip in income, a market downturn, or a particular age window can each shift the result in the user's favor. None of this makes a conversion an automatic win, since the move carries real downsides that can leave a household worse off if it is handled poorly. What follows also walks through the most common mistakes people make when using this kind of calculator, so the estimate a reader takes away is one they can actually trust.

How Does a Roth IRA Conversion Calculator Calculate Your Tax Bill?

At its core, the calculator treats the entire amount you convert as ordinary income for the year the conversion happens, then applies your marginal tax rate to that amount to arrive at an estimated tax bill. From there, it runs two projections forward at the same time: one assuming you leave the money in the Traditional IRA and pay tax on it when it is eventually withdrawn, and one assuming you convert now and let the funds grow tax-free inside the Roth. It is worth being clear about what this figure is and is not. It is a planning estimate, not a filed tax return, and it will not automatically capture every detail of your situation, including state income tax or the effect the conversion might have on other taxable income such as Social Security benefits.

The sections below walk through what to gather before you start, what each input on the calculator actually means, a full worked example on a $100,000 conversion, and how the side-by-side growth comparison between the two accounts works.

What Information Should You Gather Before Using the Calculator?

Before you sit down with the calculator, it helps to have the following on hand:

•     Your most recent federal and state tax returns, since they show your current taxable income and marginal rate, which is the starting point for estimating what a conversion would cost.

•     The balance and account type of every non-Roth IRA you hold, including Traditional, rollover, SEP, and SIMPLE IRAs, since the IRS treats these as one combined pool when a conversion is taxed.

•     A record of any non-deductible, after-tax contributions you have made over the years, since this figure sets your after-tax basis and directly feeds the pro-rata calculation covered later on this page.

•     An estimate of your income for the year you plan to convert, since the conversion is added on top of that income and can push part of it into a higher bracket than you expect.

What Inputs Does the Calculator Need From You?

Each field on the calculator plays a specific role in the estimate:

•     Current Traditional IRA balance – sets the total amount available to convert and the base the growth projection starts from.

•     Non-deductible (after-tax) contribution amount – used to work out the taxable share of the conversion under the pro-rata rule.

•     Current age and target conversion or retirement age – determines how many years the converted balance has to grow tax-free before it is needed.

•     Amount to convert – the dollar figure the calculator adds to your taxable income for the year.

•     Current marginal tax bracket – the rate applied to the converted amount today.

•     Expected tax bracket in retirement – the rate the calculator assumes would apply if the money stayed in the Traditional IRA and was withdrawn later.

•     Expected annual rate of return – drives both growth projections; many calculators default to a modest figure, some as low as 4 percent.

•     Filing status – determines which bracket thresholds and standard deduction apply to the calculation.

Entering an unrealistic rate of return or an unrealistic tax rate is the single most common way users end up with a misleading result from this kind of calculator, so it is worth using conservative, well-researched figures rather than best-case assumptions.

How Much Tax Will You Owe on a $100,000 Roth Conversion?

The underlying formula is simple: the converted amount multiplied by your marginal tax rate equals your estimated tax owed, and that amount is added to your ordinary taxable income for the year rather than taxed separately at a flat rate. Because it is added on top of your other income, a large conversion can push part of itself into a higher bracket than the one you started in.

Consider a single filer with $180,000 of other taxable income in 2026 who converts $100,000 from a Traditional IRA. Under the 2026 federal tax brackets, the 24 percent bracket for single filers runs from $105,701 to $201,775, which leaves about $21,775 of room before the next bracket begins. The first $21,775 of the conversion is taxed at 24 percent, adding about $5,226 in tax, while the remaining $78,225 spills into the 32 percent bracket, which covers income from $201,776 to $256,225, adding roughly $25,032 more. The combined federal tax on this conversion comes to about $30,258, an effective rate of just over 30 percent on the converted amount even though no single dollar of it was taxed above 32 percent.

This is the mechanism the calculator is modeling: the conversion sits on top of existing income rather than being taxed in isolation, so a conversion that looks like a flat 24 percent bill on paper can end up costing meaningfully more once bracket spillover is accounted for.

How Does the Calculator Compare Traditional IRA Growth vs Roth IRA Growth?

The calculator projects two parallel scenarios out to the same future date. In the first, the money stays in the Traditional IRA, keeps growing, and gets taxed as ordinary income whenever it is eventually withdrawn. In the second, the money is converted now, the tax is paid today, and the balance grows completely tax-free inside the Roth from that point forward. A fair comparison between the two assumes equal out-of-pocket cost in both scenarios, meaning the person converting is not quietly investing less overall just because part of their money went toward the conversion tax. Comparisons that skip this detail tend to overstate how much better the Roth path looks, since they let the Roth scenario grow on a larger effective contribution than the Traditional scenario. How much a conversion is actually worth pursuing, given all of this, is a judgment call covered later on this page, not something the growth comparison alone can answer.

How Do You Pay the Tax on a Roth Conversion?

How you cover the tax bill from a conversion is a separate decision from how much you convert, and brokerage calculators do not all default to the same assumption here even though the choice measurably changes the outcome. As a general rule, paying the conversion tax with money from outside the IRA produces a better long-term result than withholding the tax from the converted amount itself, simply because more principal stays inside the account and keeps growing tax-free.

What Happens If You Withhold the Tax From the Converted Amount?

Some calculators default to this method: the estimated tax owed is subtracted directly from the dollars being converted, so less money actually reaches the Roth IRA than the amount you started with. If the account owner is under 59 and a half, the withheld portion can also be treated as an early withdrawal and hit with a 10 percent penalty on top of ordinary tax. This is the lowest-effort option to set up, but it is usually the least favorable one financially. For example, converting $100,000 and withholding $24,000 for tax leaves only $76,000 actually landing in the Roth account, compared with the full $100,000 that would arrive if the tax were paid from another source.

What Happens If You Pay the Tax From Outside Savings or Investments?

Paying the conversion tax from a separate source, whether that is cash, a savings account, or a taxable brokerage account, keeps the full converted amount growing tax-free inside the Roth. If those outside funds come from selling taxable investments, though, any resulting capital gains carry their own tax cost, so where the money comes from still matters. Pulling from a tax-efficient account that has been held with minimal trading and deferred gains produces a better overall result than pulling from a tax-inefficient account that has been traded frequently and taxed along the way, since the second option adds an extra layer of tax on top of the conversion itself.

What Is the Break-Even Point in a Roth IRA Conversion?

Calculators generally express break-even in one of two ways. The first is a break-even year, the point at which the tax-free growth inside the Roth catches up to and overtakes the after-tax value of the Traditional IRA if it had been left alone. The second is a break-even tax rate, the future tax rate at which converting and not converting would produce exactly the same after-tax result. A shorter time horizon to retirement generally means it takes relatively longer, in relative terms, to reach break-even, since there is less time for tax-free growth to close the gap created by paying tax up front.

How Many Years Does It Take for a Roth Conversion to Pay Off?

There is no single universal answer here, since the honest response depends entirely on your own inputs, but most conversions break even somewhere between 5 and 15 years depending on the rate of return assumed and the gap between your current and expected future tax rate. The calculator's break-even output will move every time you change an input, which is exactly why it is worth testing a few different scenarios rather than relying on one estimate.

What Is the Break-Even Tax Rate (BETR) and How Does It Differ From Break-Even Year?

BETR is a more precise metric than a break-even year: it is the single future tax rate at which a person would be exactly indifferent between converting and not converting, assuming both accounts are fully liquidated at that future date. Break-even year answers the question of when a conversion pays off, while BETR answers a different question, at what future tax rate does converting stop being worth it. For example, a BETR of 26 percent means the conversion stays favorable as long as your actual future tax rate turns out to be 26 percent or higher; if your real future rate ends up lower than that, the conversion would not have been worth it in hindsight. Some advisor-grade calculators lead with BETR instead of a simple year count precisely because it isolates the one variable, future tax rate, that is hardest to predict.

What Factors Change the Break-Even Point?

Several inputs move the break-even point or BETR, roughly in order of typical impact:

•     The size of the gap between your current and future tax rate – usually the single biggest driver of the result.

•     How the conversion tax is paid – outside funds versus withheld funds meaningfully changes the amount left to grow.

•     The expected rate of return – higher assumed returns shorten the break-even year but do not change BETR.

•     The number of years until the money is needed – less time to grow means less room for the Roth path to catch up.

How Much of Your Traditional IRA Should You Convert This Year?

This is one of the most searched follow-up questions after deciding a conversion is worth considering at all, and there is no fixed dollar amount that fits everyone. The common approach is converting only enough to fill up the room remaining in your current tax bracket without spilling into the next one. Converting the full balance in a single year is rarely the right approach, since it usually forces a large chunk of the conversion into a much higher bracket than the rest.

How Does Filling Your Current Tax Bracket Guide the Conversion Amount?

The fill-the-bracket method works in three steps: start with your taxable income from all other sources, find the top of your current bracket, and convert only the difference between the two. Take a single filer in 2026 who takes the standard deduction of $16,100 and has $90,000 of wage income, putting their taxable income at $73,900, inside the 22 percent bracket which runs up to $105,700. That leaves $31,800 of room before the 24 percent bracket begins, so converting up to roughly $31,800 keeps the entire conversion inside the 22 percent bracket. The exact figures come from the IRS's annual inflation adjustments, which means this method needs to be reapplied every year, since both income and bracket thresholds change annually.

Why Is Converting Your Entire IRA at Once Usually a Mistake?

A single large conversion is added on top of all your existing income for the year, so a large portion of it can land in the highest brackets you reach rather than the lower ones you started in. A large conversion can also trigger Medicare IRMAA surcharges for anyone near or already on Medicare, a point covered in more depth later on this page. Spreading conversions across several years, often five to ten, is the more common strategy for keeping the effective tax rate on the total amount lower than a single lump-sum conversion would.

Can a Roth Conversion Calculator Model Multiple Years at Once?

Some calculators only model a single conversion event, entering one amount and seeing one year's tax impact. More advanced tools let you plan a multi-year conversion schedule and see the cumulative tax and growth effect across the entire window. What a multi-year view adds that a single-year calculator cannot is the ability to see how staying under a bracket ceiling, or an IRMAA tier, every single year rather than just once, changes both the total amount you end up converting and the total tax you pay across the full plan.

How Does the Pro-Rata Rule Affect Your Conversion Calculation?

The pro-rata rule means the IRS treats all of a person's Traditional, SEP, and SIMPLE IRA balances as one single combined pool rather than as separate accounts, so a conversion cannot cherry-pick only the after-tax portion of that pool. The taxable share of any conversion equals the pre-tax percentage of the combined pool, which often surprises people who assumed they could convert just their non-deductible contributions tax-free. This detail matters most for anyone attempting a backdoor Roth conversion while also holding an existing pre-tax IRA balance elsewhere.

What Happens When You Have Both Pre-Tax and After-Tax Money in Your IRA?

Consider three account balances: money from deductible contributions, money from non-deductible contributions, and investment growth on top of both. Suppose the combined pool across all of a person's Traditional IRAs totals $100,000, of which $5,000 represents after-tax, non-deductible basis. That basis represents 5 percent of the pool, so about 95 percent of any partial conversion from that pool is taxable, regardless of which specific dollars the person intends to convert. This calculation happens at year-end across all IRAs combined, not account by account, which is the detail most people miss when they assume they can isolate one account's after-tax contributions and convert those alone.

When Is the Best Time to Convert a Traditional IRA to a Roth IRA?

A few recurring signals make a conversion more favorable: a temporary drop in income, a market downturn, a particular age window, or simply having a financial profile suited to conversion in the first place. There is no single best age for everyone. The right time depends on when your taxable income happens to be temporarily lower than you expect it to be later.

Why Do Low-Income Years Matter for Roth Conversions?

A job gap, an early-retirement stretch before Social Security starts, or a year with unusually large deductions can all temporarily push someone into a lower bracket than usual. Converting during that window means paying tax at that lower rate instead of the higher rate that might apply in a peak-earning year. Converting $50,000 during a year taxed at 12 percent instead of a year taxed at 24 percent, for instance, cuts the federal tax on that conversion roughly in half.

How Does a Market Downturn Change the Conversion Math?

When account values drop, the same number of shares is simply worth less, so converting during a downturn means paying tax on a smaller dollar amount for the exact same underlying shares. Any later market recovery then happens entirely tax-free inside the Roth rather than being taxed on withdrawal. If an account worth $100,000 drops to $80,000 and is converted at that lower value, the tax bill is based on $80,000, and the eventual recovery back toward $100,000 and beyond grows inside the Roth without further tax. This is best treated as an opportunistic strategy rather than something to time precisely, since markets are unpredictable and waiting for a specific drop is not a reliable plan.

Should You Convert to a Roth IRA After Age 60?

Converting after 60 is common and can still work well, but the calculation shifts because there is less time left for the break-even point to be reached, and if the person is within two years of Medicare eligibility, IRMAA becomes a bigger factor in the decision. People in this age range often have unusually low income in the gap between leaving full-time work and when Social Security or required minimum distributions begin, which can make this a strong window despite the shorter runway for growth.

Which Investor Profiles Benefit Most From a Roth Conversion?

Two profiles are useful for making the timing guidance concrete. Someone who expects a lower tax bracket in retirement than they are in today generally benefits less from converting now, since they would likely pay less tax by simply waiting and withdrawing later. Someone who expects income and tax rates to rise later, whether from a pension, required minimum distributions, or simply a temporarily low-income year right now, tends to benefit more from converting while rates are still low. This is a general comparison rather than a personalized recommendation, and the calculator above is how a reader tests their own numbers against either profile.

What Are the Downsides and Risks of a Roth IRA Conversion?

A conversion creates an immediate, sometimes large, tax bill in the year it happens, and it cannot be reversed once completed. It can also trigger Medicare IRMAA surcharges or push other income, including Social Security benefits, into a more heavily taxed range. If the tax is paid from the wrong source, or the conversion is done at the wrong time, a household can end up with less total wealth than if it had never converted at all.

Can a Roth Conversion Leave You Worse Off Than Not Converting?

Yes, this is genuinely possible, and it tends to happen in one of two ways. The first is converting at a marginal rate that turns out to be higher than the eventual withdrawal rate would have been, meaning the household paid more tax than they needed to. The second is paying the conversion tax out of the IRA balance itself rather than from outside funds, which permanently shrinks the amount left inside the account to grow. In a scenario where someone converts at 32 percent expecting a similar rate in retirement, but their actual retirement rate turns out to be 12 percent, the calculator can and often does show a lower projected ending value for the conversion path than for simply leaving the money alone.

What Age and Account Limits Apply to Roth Conversion Calculators?

Some tools cap the usable age range because they do not factor in required minimum distributions, which begin at age 73, so results become unreliable for someone already subject to them. Non-deductible, after-tax contribution amounts also need to be entered separately for the pro-rata calculation to come out accurate, and a calculator that ignores this input will overstate the tax-free portion of a conversion, making the result look better than it actually would be.

What Mistakes Do People Make When Using a Roth Conversion Calculator?

The most common errors seen across forums and comment sections include entering an unrealistic rate of return, forgetting the pro-rata rule entirely, ignoring IRMAA, assuming a conversion can be undone if circumstances change, and not accounting for the tax owed on outside funds used to cover the conversion. Two of these mistakes cause the most damage and are worth walking through in more depth.

Why Do People Underestimate Their Total Tax Bill?

A few blind spots show up repeatedly: forgetting that the conversion is added on top of all other income for the year rather than taxed in isolation, not accounting for state income tax at all, and not checking whether the conversion pushes other income, such as Social Security benefits, into a more heavily taxed range. A conversion that looked perfectly reasonable at the federal level alone can grow noticeably once state tax and the Social Security effect are added on top.

Why Is a Roth Conversion Impossible to Reverse Today?

Since the Tax Cuts and Jobs Act took effect, a completed Roth conversion can no longer be recharacterized back into a Traditional IRA, which is different from a Roth contribution, which can still be recharacterized before the tax filing deadline. Once someone converts and the resulting tax bill is set, a later market drop or a change in income cannot undo that year's tax liability. This is a frequently confused point, since older articles written before the rule changed still describe conversions as reversible.

How Does a Roth Conversion Fit Into Your Broader Retirement Tax Plan?

A conversion decision rarely stands alone. It connects directly to choosing the right account type in the first place, covered in our Traditional IRA vs Roth IRA comparison; to contribution rules for higher earners, covered in our backdoor Roth IRA guide and our overview of current Roth IRA contribution limits; to what happens once withdrawals become mandatory, covered in our required minimum distributions guide; to Medicare cost planning, covered in our Medicare IRMAA guide; and to specialized strategies including the Roth conversion ladder, the five-year rule for Roth withdrawals, the interaction with Social Security taxation, and how an in-plan 401(k) or TSP Roth conversion differs from converting an IRA. Each of these gets a full explanation on its own page; the sections below exist only to connect the dots.

What Is the Difference Between a Traditional IRA and a Roth IRA?

In the context of a conversion, three things differ between the two account types: contribution tax treatment (pre-tax versus after-tax), withdrawal tax treatment (taxable versus tax-free if qualified), and the fact that only a Traditional IRA can serve as the source account in a conversion. The question that matters here is which one you are converting from and which one you are converting to, rather than a generic side-by-side comparison. Our Traditional IRA vs Roth IRA comparison covers contributions, tax treatment, withdrawal rules, and required minimum distributions side by side in full.

How Does a Backdoor Roth IRA Work for High Earners?

A backdoor Roth is a two-step process that uses the same conversion mechanics covered earlier on this page: a nondeductible Traditional IRA contribution followed immediately by a conversion to Roth. This ties directly back to the pro-rata section above, since an existing pre-tax IRA balance changes the tax outcome of a backdoor Roth in exactly the same way it changes any other partial conversion. Our backdoor Roth IRA guide walks through the full process step by step, including income-limit rules this page does not cover.

What Are the Roth IRA Contribution Limits This Year?

In the context of conversions rather than contributions, the key point is that conversion amounts are not limited by the annual contribution limit at all, which often surprises readers who assume the two work the same way. For context, the 2026 Roth IRA contribution limit is $7,500, or $8,600 for those 50 and older, with direct contributions phasing out for single filers between $153,000 and $168,000 of modified adjusted gross income and for married couples filing jointly between $242,000 and $252,000. This context explains why many readers considering a conversion are also weighing a backdoor Roth in the first place. Full details live on our Roth IRA contribution limits page, sourced from the IRS's annual notice.

How Do Required Minimum Distributions Work on a Traditional IRA?

Required minimum distributions are, for many people, the reason a conversion gets considered in the first place: a Traditional IRA forces withdrawals starting at age 73, and those withdrawals are taxed as ordinary income whether or not the money is actually needed that year. Converting some of the balance ahead of that age reduces the size of future forced withdrawals, which connects back to the earlier point that most conversion calculators are not designed for use once required minimum distributions have already begun. Our required minimum distributions guide covers the full rulebook.

How Can a Roth Conversion Affect Your Medicare IRMAA Premiums?

IRMAA uses income reported two years earlier, so a conversion done today can raise Medicare premiums two years from now, and the brackets work as a cliff rather than a gradual slope, meaning crossing a threshold by even a small amount triggers the full surcharge for that tier. For 2026, the surcharge applies once modified adjusted gross income exceeds $109,000 for single filers or $218,000 for married couples filing jointly, on top of the standard Part B premium of $202.90 a month. A conversion that looked perfectly reasonable at the federal tax level can still push a filer into a higher IRMAA tier once combined with other income sources that same year.

Our dedicated Medicare IRMAA guide covers appeals, the two-year lookback rule, and planning strategies in more depth.

What Is a Roth Conversion Ladder and How Does It Work for Early Retirement?

A conversion ladder is a repeated application of the single conversion already explained earlier on this page: converting a portion of a Traditional IRA each year and waiting five years per conversion before that specific portion can be withdrawn penalty-free. It is a strategy used by people who want to access retirement funds before age 59 and a half. This ties back to the earlier multi-year modeling section, since a ladder is exactly what that kind of multi-year view is typically used to plan out. Our Roth conversion ladder guide covers the full early-retirement strategy in detail.

What Is the Five-Year Rule for Roth IRA Withdrawals?

There are actually two separate five-year clocks, and mixing them up is a frequent source of confusion. One clock governs tax-free treatment of earnings and starts with a person's very first Roth contribution or conversion. The other governs penalty-free access to converted principal specifically, and it restarts with every separate conversion rather than running once. This connects directly back to the conversion timing discussion earlier on this page, since it affects when converted money actually becomes accessible. Our five-year rule guide walks through both clocks side by side.

How Do Roth Conversions Affect Social Security Taxation?

A Roth conversion adds to taxable income for the year, and that additional income can increase the share of Social Security benefits subject to tax, up to 85 percent of benefits, an effect sometimes called the Social Security tax torpedo. This page focuses only on that interaction; a full explanation of how Social Security benefits get taxed in general lives on our Social Security taxation guide.

How Does a 401(k) or TSP Roth In-Plan Conversion Differ From an IRA Conversion?

Employer plans such as a 401(k) or the federal Thrift Savings Plan offer a related but distinct move called an in-plan Roth conversion, where traditional plan money converts to Roth money inside the same plan rather than moving out into an external Roth IRA. The key practical difference relevant to this page is that an in-plan conversion is not subject to the IRA pro-rata rule explained earlier, since that rule applies only across IRAs, though the converted amount is still fully taxable as ordinary income in the same way. Our 401(k) and TSP Roth in-plan conversion guide helps you confirm which account context, and which calculator, actually applies to your situation.

Frequently Asked Questions

Is a Roth conversion calculator's result the exact tax I will owe?

No. It is a planning estimate based on the figures you enter, and it typically leaves out state tax and any effect on other taxable income, so the actual bill on your filed return can differ.

Can I reverse a Roth conversion once it is done?

No. Since the Tax Cuts and Jobs Act took effect, a completed conversion can no longer be recharacterized back into a Traditional IRA.

Does converting to a Roth affect my Social Security benefits?

It can. The added taxable income from a conversion may increase the share of your Social Security benefits that is subject to tax in that same year.

What is the best age to convert to a Roth IRA?

There is no single best age. The right time depends on when your taxable income is temporarily lower than you expect it to be later, which can happen at almost any age.

Do I have to convert my entire Traditional IRA in one year?

No, and doing so is usually a mistake. Converting only enough to fill your current tax bracket, often over several years, generally keeps the effective tax rate lower.