Roth Conversion Tax Calculator
Estimate the 2026 federal and state tax on a Roth conversion, the most you can convert before the next bracket, and Social Security, IRMAA and NIIT effects.
Roth Conversion Tax Calculator
Tax Year
Amount to Convert
Pre-tax money moving from a traditional IRA, 401(k), 403(b) or TSP to a Roth. If you have after-tax basis, enter only the taxable part (Form 8606).
Other Income This Year
Wages, pensions, taxable IRA/401(k) withdrawals including RMDs, interest and ordinary dividends. Include your spouse's if you file jointly. Leave out this conversion and Social Security.
Social Security Benefits
Box 5 of Form SSA-1099, both spouses if filing jointly. Enter 0 if you haven't started benefits.
Filing Status
Age
Born before January 2, 1962. Being 65+ adds to your standard deduction and qualifies you for the senior deduction.
State
Fill Up to the Top of the…
22% bracket ends at $105,700 of taxable income (single).
The last-dollar rate is measured on a $100 step, so it includes the extra Social Security and lost senior deduction that dollar pulls in.
Estimates only. Not tax or legal advice. Assumes the whole conversion is taxable. Consult a tax professional before you convert.
Room in Your Bracket
Room is measured in taxable income. Social Security and the senior deduction can move with your conversion, so the conversion that fills this room can be smaller. The max conversion figure accounts for that.
Before vs. With Conversion
Show the federal breakdown
| Line | Before | With conversion |
|---|---|---|
| Provisional income | $0 | $0 |
| Taxable Social Security | $0 | $0 |
| AGI (used as MAGI) | $0 | $0 |
| Standard deduction | $0 | $0 |
| 65+ additional | $0 | $0 |
| Senior deduction | $0 | $0 |
| Taxable income | $0 | $0 |
| Federal income tax | $0 | $0 |
What to Watch
- The conversion is taxed as ordinary income on top of your other income.
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Covering conversion tax with extra paycheck withholding? Pay44 shows what a W-4 change does to each check, with federal and state withholding for all 50 states.
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How a Roth conversion is taxed in 2026
When you move pre-tax money from a traditional IRA, 401(k), 403(b) or TSP into a Roth account, the taxable part counts as ordinary income for the year. It's reported on Form 1099-R. IRA conversions also go on Form 8606, and the taxable amount lands on Form 1040 line 4b (line 5b for a workplace plan).
From there it stacks on top of your wages, pension, RMDs and interest, and it's taxed at whatever bracket rates those dollars reach. "Filling the bracket" means converting just enough to reach the top of a bracket you're comfortable paying, without spilling into the next one.
The table shows where each target bracket ends in 2026. The figures are taxable income, meaning income after the standard deduction.
| Top of the bracket | Single | Married jointly | Head of household | Married separately |
|---|---|---|---|---|
| 12% | $50,400 | $100,800 | $67,450 | $50,400 |
| 22% | $105,700 | $211,400 | $105,700 | $105,700 |
| 24% | $201,775 | $403,550 | $201,750 | $201,775 |
| 32% | $256,225 | $512,450 | $256,200 | $256,225 |
| Standard deduction | $16,100 | $32,200 | $24,150 | $16,100 |
| 65+ add-on (each) | $2,050 | $1,650 | $2,050 | $1,650 |
The calculator reports two rates. The effective rate is the added tax divided by the amount converted. The marginal rate is what the last converted dollar costs, and for retirees it's often well above the bracket rate. The marginal vs effective tax rate calculator and the federal tax bracket calculator go deeper on both.
Why "fill the bracket" math breaks for retirees
The usual shortcut is bracket top minus taxable income. That works for someone living on wages. It fails once Social Security or the senior deduction is in the picture, because the conversion changes more than one line of your return.
The Social Security tax torpedo. The IRS adds your other income, the conversion and half your benefits to get provisional income. Above $25,000 (single) or $32,000 (joint), up to 50% of benefits become taxable. Above $34,000 or $44,000, up to 85% can be. Those thresholds date from 1983 and 1993 and have never been indexed, so they catch more retirees every year. In the 85% zone, each converted dollar adds $1.85 of taxable income.
The senior deduction phase-out. From 2025 through 2028, each filer 65 or older gets an extra $6,000 deduction, reduced by 6% of MAGI above $75,000 ($150,000 joint). Inside that range, each converted dollar also removes 6 cents of deduction per qualifying person.
Here's what the last converted dollar costs in each case:
| Where the last dollar lands | 12% bracket | 22% bracket | 24% bracket |
|---|---|---|---|
| No Social Security or phase-out effect | 12% | 22% | 24% |
| Social Security 50% zone | 18% | 33% | 36% |
| Social Security 85% zone (torpedo) | 22.2% | 40.7% | 44.4% |
| Senior phase-out, one person 65+ | 12.7% | 23.3% | 25.4% |
| Senior phase-out, both spouses 65+ | 13.4% | 24.6% | 26.9% |
| 85% zone plus phase-out, one person | 23.5% | 43.1% | 47.1% |
Worked example. A single filer, 65+, has a $10,000 pension and $28,000 of Social Security in 2026. Before converting, provisional income is $24,000, so none of the benefits are taxable. AGI is $10,000, and $14,150 of the $24,150 in deductions ($16,100 standard, $2,050 add-on and the $6,000 senior deduction) goes unused.
The shortcut says $50,400 plus $14,150, or $64,550, fits in the 12% bracket. The real answer is $40,750. By that point 85% of the benefits ($23,800) has become taxable, AGI is $74,550 and taxable income is exactly $50,400. Federal tax on the $40,750 is $5,800, an effective 14.2%. Converting the shortcut's $64,550 instead would put $25,201 in the 22% bracket and start eating the senior deduction.
That's why the years between retiring and claiming Social Security or starting RMDs are often the cheapest time to convert. Provisional income is low, and there are no benefits for the conversion to drag into the tax base.
Thresholds to watch before you convert
Medicare IRMAA. Medicare sets Part B and Part D premiums from your MAGI two years earlier, so if you're 63 or older, a 2026 conversion can raise your 2028 premiums. The 2026 first surcharge tier starts above $109,000 of MAGI for individual returns and $218,000 for joint returns. The tiers are cliffs: $1 over costs the full surcharge for the year. The 2028 thresholds will be adjusted for inflation, so the calculator's flag uses the 2026 figures as a cautious marker.
The 3.8% net investment income tax. NIIT applies once MAGI passes $200,000 (single or head of household), $250,000 (joint) or $125,000 (married filing separately). A conversion isn't investment income, but it raises MAGI, which can expose interest, dividends, capital gains and rental income to the extra 3.8%.
The end of the senior deduction. The $6,000 per person is fully gone at $175,000 of MAGI ($250,000 joint).
The flags only reflect the amount you enter. A larger conversion, like the max figure for your target bracket, can cross a threshold the entered amount doesn't, so check both. To see what counts toward the income figure behind all three, try the AGI calculator.
Paying the tax and timing the conversion
Pay the tax from savings or a taxable account if you can. Money withheld from the conversion never reaches the Roth. It's treated as a distribution, and if you're under 59½ you can owe the 10% additional tax on it.
The tax is due for the year of the conversion. A large conversion can call for an estimated payment or extra withholding to avoid an underpayment penalty; the quarterly estimated tax calculator helps size it. If you'd rather cover it through your paycheck, Pay44 shows what a W-4 change does to each check.
A conversion counts for the year it's completed, so the deadline is December 31, 2026, and conversions can't be undone (recharacterized). Each conversion starts its own five-year clock for the 10% additional tax if you're under 59½. If you have after-tax money in any traditional IRA, the pro-rata rule on Form 8606 makes part of every conversion tax-free, so enter only the taxable part above. Still deciding between Roth and pre-tax savings going forward? The Roth vs traditional 401(k) calculator covers new contributions.
Estimates only. Not tax or legal advice. This calculator assumes the whole conversion is taxable (no after-tax basis or pro-rata rule) and uses the 2026 federal brackets, standard deduction, 65+ add-on and senior deduction, assuming a valid SSN for the senior deduction. It doesn't model qualified dividends or capital gains stacking (a conversion can push them from the 0% rate to 15%), tax-exempt interest, Schedule 1 adjustments, itemized deductions, credits, the blind add-on, the 5-year rules or estimated-tax timing. State figures use each state's regular income tax table, with no retirement-income exclusions and no state tax on Social Security. Married filing separately assumes you lived with your spouse at some point in 2026 and leaves out your spouse's 65+ add-on. IRMAA flags use the 2026 thresholds, while a 2026 conversion sets 2028 premiums, and those thresholds will differ.
Frequently Asked Questions
Common questions about roth conversion tax calculator
How much tax will I pay on a Roth conversion?
The taxable part of a conversion is ordinary income for the year. It stacks on top of your other income and is taxed at your federal bracket rates (10% to 37% in 2026), plus state income tax where your state taxes it. For example, a single filer under 65 with $58,000 of other income has $41,900 of taxable income after the $16,100 standard deduction. A $25,000 conversion fills the last $8,500 of the 12% bracket (which ends at $50,400) for $1,020 and puts the other $16,500 in the 22% bracket for $3,630. The federal bill is $4,650, about 18.6% of the amount converted. Social Security and the senior deduction can push the cost higher, and the calculator above accounts for both.
How much can I convert without moving into a higher tax bracket?
With no Social Security and no senior deduction in play, it's the top of your bracket minus your taxable income. In 2026 the 12% bracket ends at $50,400 of taxable income for single and separate filers, $100,800 for joint filers and $67,450 for heads of household. The 22% bracket ends at $105,700 for everyone except joint filers ($211,400). If you collect Social Security or are 65 or older, that subtraction overstates your room, because each converted dollar can also make up to 85 cents of benefits taxable and shrink the $6,000 senior deduction. In one example (single, 65+, $10,000 of pension, $28,000 of Social Security), the simple math says $64,550 fits in the 12% bracket, but the real answer is $40,750. The calculator solves for the exact amount.
Will a Roth conversion raise my Medicare premiums?
It can. Medicare's income-related surcharge (IRMAA) uses your modified AGI from two years earlier, so a 2026 conversion sets your 2028 Part B and Part D premiums. That matters if you're 63 or older this year. For 2026 the first surcharge tier starts above $109,000 of MAGI for individual returns and $218,000 for joint returns. It adds $81.20 a month to the $202.90 standard Part B premium, plus a Part D surcharge. The tiers are cliffs: going $1 over triggers the full amount. The 2028 thresholds will be adjusted for inflation. The AGI calculator shows what goes into the income figure.
Can I pay the conversion tax out of the IRA itself?
You can, but it usually costs more. Any amount withheld for taxes isn't converted. It's treated as a regular distribution, so it's taxable, and if you're under 59½ it can also owe the 10% early-distribution additional tax. The conversion itself is never subject to the 10% tax. Paying the bill from savings or a taxable account keeps the full amount growing tax-free in the Roth. Because the tax is due for the year of the conversion, you may need to make an estimated payment or raise withholding to avoid an underpayment penalty. The quarterly estimated tax calculator can help you size that payment.
Does a Roth conversion make more of my Social Security taxable?
Yes, if you're receiving benefits. The IRS counts your other income, the conversion and half your benefits as "provisional income." Once that passes $25,000 (single) or $32,000 (joint), up to 50% of benefits become taxable. Past $34,000 or $44,000, up to 85% can be. These thresholds are set by law and have never been adjusted for inflation. In the 85% zone each converted dollar adds $1.85 of taxable income, so a 12% bracket behaves like 22.2%. Qualified Roth withdrawals later don't count toward provisional income, which is one reason people convert before claiming benefits.
Is there a penalty or a 5-year rule on Roth conversions?
There's no 10% penalty on the conversion itself, but there are two separate five-year clocks. First, each conversion has its own five-year period: if you're under 59½ and withdraw converted dollars within five years, the 10% additional tax can apply to them. Second, earnings come out tax-free only in a qualified distribution, which requires five years since your first Roth IRA contribution or conversion and age 59½ (or disability or death). Conversions made in 2018 or later can't be undone (recharacterized). To count for 2026, a conversion must be completed by December 31, 2026.
Do I owe state tax on a Roth conversion?
In most states with an income tax, yes: the conversion is taxed as ordinary income at your state rate. The nine states without a broad income tax (Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington and Wyoming) don't tax it. Illinois, Pennsylvania and Mississippi generally don't tax conversions either. Some other states offer partial retirement-income exclusions. This calculator doesn't apply them, so check your state's rules.
How does the 2026 senior deduction change the math?
Filers who are 65 or older by the end of 2026 can deduct an extra $6,000 each (2025 through 2028), on top of the regular 65+ standard deduction add-on ($2,050 for single or head of household, $1,650 per spouse for married filers). It shrinks by 6% of MAGI above $75,000 ($150,000 on a joint return) and is gone at $175,000 ($250,000 joint). Married couples must file jointly to claim it. Inside that range, every converted dollar also takes away 6 cents of deduction per qualifying spouse, so a 22% bracket behaves like 23.3% (24.6% for a couple who both qualify).