Tax
Roth Conversion Calculator
See the tax bill on moving money into a Roth, how much room is left in your bracket, and whether paying now beats paying later.
Uses 2026 federal brackets. The conversion is added on top of your other income, so it’s taxed at your highest rates.
Heads up: the 2026 federal figures in this tool (the standard deduction and the brackets) are still waiting on our CPA’s check against the IRS tables. Read the results as approximate until this note is gone.
What this means
Converting $20,000 adds about $3,200 to this year’s tax bill, 16% of the amount. It all stays in the 12% bracket, with $10,800 of room still left.
If your tax rate in retirement really is 22%, converting leaves you about $5,402 more after tax in 20 years. The comparison turns almost entirely on that one guess: a conversion wins when today’s rate is lower than the rate you’d pay later.
Pay the tax from savings, not from the converted money. Paying it out of the account leaves less in the Roth to grow tax-free ($53,880 instead of $64,143 here), and under age 59½ the part held back for tax can also be hit with an early-withdrawal penalty.
The extra income can also raise Medicare premiums or shrink health-insurance subsidies. This is an estimate, not tax advice. A tax pro can check it against your full return before you convert.
These are estimates to help you think, not personalized legal, tax, or investment advice, and not a promise of any result.
This calculator estimates the tax bill on converting money from a traditional IRA or 401(k) to a Roth, and whether paying that tax now leaves you more later. Enter your income, the amount to convert and a few assumptions, and it shows the federal and state tax, the rate the conversion is taxed at, the room left in your bracket, and the after-tax value both ways.
Why it matters: a conversion trades a tax bill today for tax-free withdrawals later. Whether that trade pays depends mostly on one comparison, your tax rate now against your tax rate in retirement, and on how much you convert at once. Converting a little in a low-income year can make sense; converting too much at once can push the extra into a higher bracket.
How to use it
Enter this year's taxable income
Your income after deductions, without the conversion. For most people that's total income minus pre-tax deductions minus the standard deduction. The conversion stacks on top of it.
Try different amounts to convert
Watch the room left in your bracket. Converting up to that amount keeps every converted dollar at your current rate. Going past it means the extra is taxed at the next rate up.
Set your assumptions honestly
The years until you'd withdraw, an assumed return, and the tax rate you expect in retirement. The retirement rate decides the answer, so try a few. Nobody knows it for sure.
Behind the numbers
It's taxed as income, on top
A conversion counts as ordinary income in the year you do it, added to everything else. That's why it's taxed at your highest rates, and why the size of the conversion matters as much as whether you do it.
Pay the tax from outside the account
If you pay the tax with savings, the full converted amount grows tax-free in the Roth. If the tax comes out of the converted money, less goes into the Roth, and under age 59½ the part held back can also be treated as an early withdrawal with a penalty.
Rate now vs. rate later
If your tax rate when you withdraw would be higher than the rate you pay to convert, converting comes out ahead. If it would be lower, leaving the money in the traditional account usually wins. A year with unusually low income (a layoff, a gap between jobs, early retirement) is often when conversions look best.
The math behind it
Federal tax on the conversion is your tax with the conversion added minus your tax without it. State tax is your state rate times the amount. Later, the Roth is worth the amount grown at your assumed return, tax-free. Not converting, the traditional account grows the same way and is taxed at your retirement rate on the way out, and the money you didn't spend on the conversion tax grows alongside it (its growth taxed at the same retirement rate, as a stand-in for a taxable account). Compare the two totals.
Worked example
A married couple with $70,000 of taxable income converts $20,000, with a 4% state tax, using this year's federal figures. The whole conversion fits in the 12% bracket, so federal tax is $2,400 and state is $800: $3,200 total. They still had $30,800 of room in that bracket. Over 20 years at an assumed 6%, the Roth grows to about $64,143. Not converting, at a 22% retirement rate, leaves about $58,740 after tax, so converting comes out about $5,402 ahead. Paying the $3,200 from the converted money instead would leave about $53,880 in the Roth. (The federal figures behind this example are still waiting on our CPA's check against the IRS tables; read them as approximate.)
Fill the bracket, not past it
Find the room left in your current bracket and convert up to that amount, not more. Every dollar stays at today's rate. If today's rate is lower than what you expect in retirement, that's the conversion that most often pays.
Common questions
How much tax will I owe on a Roth conversion?
The converted amount is added to your income for the year and taxed at your top federal rate, plus any state tax. The calculator figures it as the difference between your federal tax with the conversion and without it, so a conversion that crosses a bracket line is taxed correctly at each rate.
Is there a limit on how much I can convert?
There's no income limit on conversions and no cap on the amount. The practical limit is the tax bill and your bracket: converting only the room left in your current bracket keeps the cost at your current rate.
Can I take the converted money out right away?
Each conversion has its own five-year clock. If you're under 59½ and withdraw converted money within five years, a 10% penalty can apply. Check the IRS rules or ask a tax pro before converting money you might need soon.
Are there other costs to the extra income?
Possibly. The higher income in the conversion year can raise Medicare premiums a couple of years later or shrink health-insurance marketplace subsidies. This calculator doesn't model those, so factor them in if they apply to you.
Sources & references
Go deeper
The calculator gives you a number. The Retirement Accounts Brick teaches you what to do with it, in plain English. And if you’re not sure where to start, the free BrickScore Assessment checks your whole foundation in about 5 minutes.
first the number, then the move