Roth Conversion Calculator (2026)
Estimate the federal tax on converting traditional IRA money to a Roth IRA, and see whether it pushes you into a higher bracket.
Estimate Your Roth Conversion Tax
2026 federal brackets differ by filing status.
Your taxable income for 2026, not counting the conversion. Subtract your standard deduction first.
The amount you plan to move from a traditional IRA to a Roth IRA in 2026.
State income tax is excluded. Some states tax conversions too, so your total bill may be higher. This is a federal estimate only.
How Bracket Fill Works
A Roth conversion is taxed as ordinary income in the year you convert, and it stacks on top of your other income. That stacking is what makes bracket fill matter. Your existing income fills the lowest brackets first, and the conversion fills whatever space is left in your current bracket before spilling into the next one. So a $20,000 conversion is rarely taxed at one flat rate: part of it may be taxed at 12%, part at 22%, and part at 24%, depending on where your income already sits.
This is why converting in a low-income year is so powerful. If you retire early, take a career break, or have a year with unusually low earnings, your brackets have empty room, and a conversion can be taxed at 12% or even 10%. The same conversion in a high-earning year could be taxed mostly at 24% or 32%. The calculator shows the blended effective rate on the conversion, which is the number that actually matters, alongside the marginal bracket you land in after converting.
The 2026 Federal Tax Brackets Used Here
These are the 2026 federal income tax brackets published in IRS Revenue Procedure 2025-32. The calculator applies them to taxable income, which is why you enter income after subtracting your standard deduction.
| Rate | Single: taxable income up to | Married filing jointly: taxable income up to |
|---|---|---|
| 10% | $12,400 | $24,800 |
| 12% | $50,400 | $100,800 |
| 22% | $105,700 | $211,400 |
| 24% | $201,775 | $403,550 |
| 32% | $256,225 | $512,450 |
| 35% | $640,600 | $768,700 |
| 37% | Above $640,600 | Above $768,700 |
The Formula
Federal tax is computed bracket by bracket: each slice of taxable income is taxed at its own rate, and the slices are added together. The conversion tax is simply the difference between the tax on your income plus the conversion and the tax on your income alone.
Tax after = tax on (taxable income before conversion plus conversion amount)
Conversion tax = tax after minus tax before
Effective rate on conversion = conversion tax / conversion amount
Marginal bracket after = the rate on your last dollar of income after converting
Worked Example: Single, $60,000 Before, $20,000 Conversion
| Calculation | Amount | |
|---|---|---|
| Tax before conversion | $1,240 plus $4,560 plus 22% of $9,600 | $7,912.00 |
| Tax after conversion ($80,000) | $1,240 plus $4,560 plus 22% of $29,600 | $12,312.00 |
| Conversion tax | $12,312.00 minus $7,912.00 | $4,400.00 |
| Effective rate on conversion | $4,400.00 / $20,000 | 22.0% |
| Marginal bracket after | $80,000 falls in the 22% bracket | 22% |
In this example the whole conversion stays inside the 22% bracket, so the effective rate equals the marginal rate. When a conversion crosses a bracket boundary, the effective rate is a blend, and the calculator flags the crossing with a bracket-fill warning.
The December 31, 2026 Deadline
A Roth conversion counts in the calendar year it is completed, not the year you start thinking about it. To count for 2026, the money must actually move into the Roth IRA by December 31, 2026. There is no extension, and unlike IRA contributions, there is no “until tax day” grace period for conversions. If you are planning a 2026 conversion, start the paperwork well before December so a custodian delay does not push it into 2027.
Also note that since 2018, Roth conversions cannot be recharacterized. Once you convert, you cannot undo it if the market falls or your tax situation changes. That makes the size of the conversion worth planning carefully: many people convert just enough to fill their current bracket, and no more.
The 5-Year Rule, Briefly
Converted money follows its own 5-year clock. Each conversion has a 5-year holding period, and if you withdraw converted principal before that clock runs out and you are under age 59 and a half, a 10% early-withdrawal penalty can apply to the converted amount. Earnings in a Roth IRA have a separate 5-year rule: qualified, tax-free withdrawals of earnings generally require the Roth IRA to be at least 5 years old and you to be at least 59 and a half. Keep conversions you may need soon in mind when sizing them.
When a Conversion Pays Off, and When It Does Not
- It tends to pay off when your rate now is lower than your rate later. Low-income years, early retirement before Social Security and required minimum distributions begin, and years with large deductions are classic conversion windows.
- It pays off when you can pay the tax from outside the IRA. Paying the conversion tax from a taxable account lets the full converted amount keep growing tax-free. Paying it from the converted money itself shrinks the Roth balance and, under 59 and a half, can trigger a penalty on the withheld part.
- It may not pay off if you expect a lower rate in retirement. If you will be in a lower bracket later, paying tax now at a higher rate is a loss, not a saving.
- It may not pay off if the tax bill strains your cash. A conversion that forces you to sell investments or dip into emergency savings is rarely worth it, however good the rate looks.
- Watch side effects. Extra income from a conversion can raise Medicare premiums (IRMAA), reduce ACA subsidies, or push capital gains into a higher rate. The calculator covers federal income tax only.
What This Calculator Does Not Cover
- State tax. Most states tax conversions as income. Add your state rate on top of the federal figure for a full estimate.
- Credits, deductions beyond the standard deduction, and the alternative minimum tax. Itemized deductions, credits, and AMT can change your real bill.
- IRMAA and subsidy effects. Higher income can raise Medicare Part B and D premiums two years later and cut premium tax credits.
- Required minimum distributions. RMDs cannot be converted; only money above your RMD for the year can move to a Roth.
