Backdoor Roth 2026: $1,565 of tax at 24% from a $50,000 IRA
The 2026 Roth IRA income limit starts at $153,000 single and $242,000 joint. Above it, the pro-rata rule decides what a backdoor conversion costs.
On this page 6 sections
For 2026, direct Roth IRA contributions phase out between $153,000 and $168,000 of modified adjusted gross income for single filers and between $242,000 and $252,000 for married couples filing jointly, so higher earners use the backdoor: a nondeductible traditional IRA contribution of up to $7,500 ($8,600 at 50 or older), converted to a Roth IRA. If you also hold pre-tax money in any traditional, SEP or SIMPLE IRA on December 31, the pro-rata rule makes most of the conversion taxable: with $50,000 there, $6,522 of a $7,500 conversion is taxed, about $1,565 at a 24% bracket, unless that money is moved into an employer plan such as a 401(k) by year-end.
The backdoor itself is two ordinary steps the tax code allows at any income. What decides whether it is tax-free is not the contribution but everything else in your IRAs on the last day of the year.
The numbers
Every figure below comes from the MoneyVibe backdoor Roth calculator, which runs the Form 8606 arithmetic. Inputs: a $7,500 nondeductible contribution made in 2026 and converted in full in 2026, no after-tax money from earlier years, no growth before the conversion, and the taxable part priced at a 24% federal bracket. The only thing that changes from row to row is the pre-tax money in other traditional, SEP and SIMPLE IRAs on December 31. Dollar amounts are rounded to the nearest dollar.
| Other pre-tax IRA money on December 31, 2026 | Share of the conversion that is tax-free | Taxable part of the $7,500 | Federal tax at 24% |
|---|---|---|---|
| $0 | 100% | $0 | $0 |
| $10,000 | 42.86% | $4,286 | $1,029 |
| $25,000 | 23.08% | $5,769 | $1,385 |
| $50,000 | 13.04% | $6,522 | $1,565 |
| $100,000 | 6.98% | $6,977 | $1,674 |
| $250,000 | 2.91% | $7,282 | $1,748 |
The tax-free share is your after-tax money divided by the whole pool. With $50,000 of pre-tax IRA money, the $7,500 you put in is $7,500 of $57,500, or 13.04%. So $978 of the conversion comes out tax-free and $6,522 is added to your income. Even a $10,000 rollover IRA from an old job turns more than half of the conversion into taxable income. The tax is not a fee: the $6,522 taxed is pre-tax money that now sits in the Roth IRA, paid for years earlier than planned.
The $6,522 of after-tax money you did not use is not lost. Form 8606 carries it forward as basis (line 14), and it comes out tax-free in proportion when that IRA money is later converted or withdrawn. The pro-rata rule changes when the after-tax money is recovered; it does not erase it.
Why it works this way
The income limits. IRS Notice 2025-67 sets the 2026 IRA contribution limit at $7,500, with a $1,100 catch-up from age 50; the Form 8606 instructions and Publication 590-A apply one limit to all traditional and Roth IRAs together. The notice puts the Roth IRA phase-out range at $153,000 to $168,000 for single filers and heads of household, $242,000 to $252,000 for married couples filing jointly (and a qualifying surviving spouse), and $0 to $10,000 for married filing separately. Publication 590-A adds that someone filing separately who did not live with their spouse at any time in the year uses the single range. Inside a range the direct contribution is reduced; above it, it is zero. A traditional IRA contribution has no income limit (it only needs taxable compensation, yours or a spouse's on a joint return), and neither does a conversion. That is the whole backdoor.
The pool. Internal Revenue Code section 408(d)(2) says that for taxing IRA distributions "all individual retirement plans shall be treated as 1 contract" and that the value is computed "as of the close of the calendar year". The Form 8606 instructions apply this to every traditional IRA, which for the form includes SEP and SIMPLE IRAs ("a traditional IRA is any IRA that isn't a Roth IRA"). Line 6 asks for the value of all of them as of December 31 (plus any outstanding rollovers), line 7 other distributions, line 8 the amount converted, line 9 adds lines 6 to 8, line 10 divides line 5 (your basis, less any contribution made in the new year for the prior year) by line 9, and line 18 is the taxable part. A 401(k), 403(b) or other employer plan is not an IRA, so it is not in the pool. Each spouse files a separate Form 8606 for their own IRAs.
The way out. Publication 590-A says a traditional IRA distribution may be rolled into a qualified plan, but "the part of the distribution that you can roll over is the part that would otherwise be taxable", and plans "may, but aren't required to, accept such rollovers". Section 408(d)(3)(H) treats the rolled amount as pre-tax money first. So the pre-tax dollars can leave for a 401(k), the after-tax dollars stay, and with nothing else in the pool on December 31 the conversion is tax-free. The Form 8606 instructions also say a distribution rolled into a qualified plan does not go on line 7.
The paperwork. You file Form 8606 for any year you make a nondeductible contribution or convert. Not filing for a nondeductible contribution costs a $50 penalty and overstating one costs $100, unless you show reasonable cause; the bigger cost of a missing form is that the IRS has no record of your basis. These rules are quoted from the 2025 Form 8606 instructions, the latest published when this was written; the 2026 limits come from Notice 2025-67.
What changes the answer
- After-tax money already in the IRA. If $20,000 of a $50,000 IRA is basis from earlier nondeductible contributions, 47.83% of the conversion is tax-free, $3,913 is taxable (about $939 at 24%), and $23,913 of basis carries forward. Your basis is on line 14 of the last Form 8606 you filed.
- Your bracket. The taxable part is ordinary income at your marginal tax rate, so the same $50,000 IRA costs $1,565 at 24% and $2,413 at 37%, as the chart shows. The tax bracket calculator shows your rate.
- What lands in an IRA before December 31. The test date is the end of the year of the conversion, not the day you convert. Convert in February with an empty IRA, then roll a $100,000 401(k) from a job you left into an IRA in November, and $6,977 of the February conversion becomes taxable, about $1,674 at 24%. Rolling that old 401(k) into the new employer's plan instead keeps the pool empty.
- Age 50 or older. The limit rises to $8,600. With $50,000 of pre-tax IRA money, $7,338 of that conversion is taxable (about $1,761 at 24%); with none, all $8,600 converts tax-free.
What to do first
- Add up every traditional, SEP and SIMPLE IRA you hold (not Roth IRAs, not 401(k)s), and find your basis on line 14 of your most recent Form 8606. Then project what will be in them on December 31, 2026, including any 401(k) you plan to roll into an IRA this year.
- Enter those figures in the backdoor Roth calculator. It splits the conversion into its tax-free and taxable parts, prices the tax at your bracket and fills in the Form 8606 lines.
- If the pool holds pre-tax money, ask your current employer's plan whether it accepts incoming IRA rollovers, and complete the move before December 31. Then contribute, convert, and file Form 8606 with your return. The calculator stops at the conversion; to see what the converted dollars could grow to tax-free over 20 years, a compound interest calculator takes the next step.
What this does not model
Growth between the contribution and the conversion (any earnings converted are taxable), a contribution made between January 1 and April 15 for the prior year, the reduced direct Roth contribution inside the phase-out range (the calculator only says whether you are below, inside or above it), married filing separately, inherited IRAs (figured on a separate Form 8606), state income tax, and a taxable amount large enough to cross into the next bracket. If your plan allows after-tax 401(k) contributions, the mega backdoor Roth calculator covers that separate route.
Common questions
What is the Roth IRA income limit for 2026?
Direct contributions phase out between $153,000 and $168,000 of modified AGI for single filers and heads of household, and between $242,000 and $252,000 for married couples filing jointly or a qualifying surviving spouse. Married filing separately (if you lived together at any time in the year) is $0 to $10,000.
Does the pro-rata rule apply to my 401(k)?
No. It covers traditional, SEP and SIMPLE IRAs only, so money in a 401(k) or 403(b) does not count. If your plan accepts incoming rollovers, moving $50,000 of pre-tax IRA money into a 401(k) before December 31 cuts the tax on a $7,500 conversion from about $1,565 to $0 at 24%.
Which balance counts, the day I convert or December 31?
December 31 of the year you convert. A $100,000 rollover into an IRA in November makes $6,977 of a $7,500 conversion done in February taxable.
Is the basis lost when the conversion is pro-rated?
No. With $50,000 of pre-tax IRA money, $6,522 of your $7,500 basis carries forward on Form 8606 line 14 and comes out tax-free in proportion later.
Do I need to file Form 8606 for a backdoor Roth?
Yes, in each year you make the nondeductible contribution or the conversion. Not filing for a nondeductible contribution carries a $50 penalty unless you show reasonable cause.
Next steps: run your own figures in the backdoor Roth calculator, read the library chapter the backdoor and mega backdoor Roth, or see the glossary entries for Roth vs traditional and the marginal tax rate.
Not tax or legal advice. Federal rules as published by the IRS in Notice 2025-67, Publications 590-A and 590-B and the Form 8606 instructions, read on October 12, 2026; confirm with a tax professional before acting.