The pro rata rule applies to each spouse separately, so your spouse’s IRA never enters your Form 8606 calculation, even on a joint return. Only IRAs in your own name count. One spouse can hold a $150,000 rollover IRA while the other converts $7,500 with $0 of taxable income.
Can I do a backdoor Roth if my spouse has an IRA?
Yes. A spouse’s traditional, rollover, SEP or SIMPLE IRA has no effect on your backdoor Roth, because Form 8606 Line 6 asks only for the value of “all your traditional IRAs” on December 31. If you hold no other pre-tax IRA money, your $7,500 conversion in 2026 produces $0 of taxable income whatever your spouse holds.
A joint return merges income and leaves IRAs alone. Joint income sets the $242,000 to $252,000 Roth contribution phase-out in Notice 2025-67, and joint compensation supports a spousal contribution. IRA balances and after-tax basis stay with each owner, so your spouse’s conversion is measured against your spouse’s accounts. The Line 5 to Line 11 arithmetic is laid out in the pro rata rule formula for a Roth conversion. Two spouses can each run this in the same year, up to $15,000 combined under 50, as the 2026 backdoor Roth limits show. Filing separately carries different costs, set out in Roth conversion married filing separately.
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Why does the pro rata rule stop at your spouse when you are married filing jointly?
The statute aggregates IRAs by the person receiving the money, and a joint return never changes who that is. IRC 408(d)(1) taxes an IRA payment to “the payee or distributee,” and 408(d)(2)(A) then treats “all individual retirement plans” as one contract, with the rollover rule in 408(d)(3)(H)(ii)(II) spelling it out as “all individual retirement plans of the distributee.”
Neither provision mentions marriage. An IRA is a single-owner account by definition: 408(a) describes a trust “for the exclusive benefit of an individual or his beneficiaries.” The Form 8606 instructions carry that onto the joint return: “If both you and your spouse are required to file 2025 Form 8606, file a separate 2025 Form 8606 for each of you,” showing only the name and SSN of the spouse whose information is reported.
Find your household: each spouse’s taxable share of a $7,500 conversion in 2026
In these six couples, both spouses contribute $7,500 nondeductibly and convert it in 2026, and each taxable share is set only by that spouse’s own December 31 balance. A spouse with no other IRA lands at $0 taxable in every row, while a spouse with a balance ranges from 84.2% to 98.2% taxable.
| Row | Couple | A: other pre-tax IRAs, Dec 31 | A: taxable part of $7,500 | B: other pre-tax IRAs, Dec 31 | B: taxable part of $7,500 | Joint return, Form 1040 line 4b |
|---|---|---|---|---|---|---|
| 1 | One spouse holds a rollover IRA | $150,000 | $7,140 (95.2%) | $0 | $0 (0.0%) | $7,140 |
| 2 | Both spouses hold IRAs | $400,000 | $7,365 (98.2%) | $40,000 | $6,315 (84.2%) | $13,680 |
| 3 | A works; B has a spousal IRA plus an old rollover IRA | $0 | $0 (0.0%) | $60,000 | $6,667 (88.9%) | $6,667 |
| 4 | A holds a SEP IRA | $210,000 | $7,245 (96.6%) | $0 | $0 (0.0%) | $7,245 |
| 5 | Texas couple: rollover IRA built during the marriage, titled to A | $250,000 | $7,282 (97.1%) | $0 | $0 (0.0%) | $7,282 |
| 6a | A holds a rollover IRA on Dec 31 | $180,000 | $7,200 (96.0%) | $0 | $0 (0.0%) | $7,200 |
| 6b | Same couple: A rolled it into A’s own 401(k) by Dec 31 | $0 | $0 (0.0%) | $0 | $0 (0.0%) | $0 |
Assumptions: no prior basis, earnings or other distributions; balances flat through December 31, 2026; Line 10 rounded to 3 places; line numbers from the 2025 Forms 8606 and 1040, the revisions the IRS currently posts. Hypothetical figures, not a projected result.
The tax sits entirely with the account holder. Row 1 reports $7,140 on the joint return; a pooled household calculation, which the law does not use, would report $13,635 on the same $15,000. Small balances still matter: row 2’s spouse B, with $40,000, is 84.2% taxable, and a forgotten $1,000 IRA makes a $7,500 conversion 11.8% taxable ($885). Row 4 follows because Form 8606 defines “traditional IRA” to include SEP and SIMPLE IRAs. The self-employed routes out are on the SEP and SIMPLE IRA pro rata page.
Worked example: row 1 on the couple’s two forms.
| Form 8606 | Spouse A | Spouse B |
|---|---|---|
| Line 5: basis | $7,500 | $7,500 |
| Line 6: own IRAs, Dec 31 | $150,000 | $0 |
| Line 8: converted | $7,500 | $7,500 |
| Line 9: lines 6 + 7 + 8 | $157,500 | $7,500 |
| Line 10: line 5 divided by line 9 | 0.048 | 1.000 |
| Line 11: nontaxable part | $360 | $7,500 |
| Line 14: basis carried to 2027 | $7,140 | $0 |
| Line 18: taxable, to Form 1040 line 4b | $7,140 | $0 |
Form 1040 line 4a shows $15,000 from the two Forms 1099-R, and line 4b shows $7,140, the sum of the two Line 18 amounts. If that income falls inside the 24% bracket, which tops out at $403,550 of taxable income for joint filers in 2026 (Rev. Proc. 2025-32), the added federal income tax is about $1,714. Spouse A’s $7,140 of basis is not lost: Line 14 carries it to A’s 2027 form, where it reduces tax on A’s later conversions and distributions.
Backdoor Roth for a non-working spouse: whose balance sets the taxable share?
The non-working spouse’s own balance sets it, because the spousal rule moves compensation and not IRAs. IRC 219(c) lets a joint filer count the other spouse’s compensation to fund a contribution of up to $7,500 in 2026, but the money lands in the lower earner’s own IRA, and that person’s Line 6 decides the result.
Row 3 separates the two rules. Spouse B left a job with a $60,000 rollover IRA and now has no earnings. Spouse A’s salary qualifies B to contribute (two full contributions take $15,000 of compensation, since 219(c)(1)(B)(ii) reduces A’s compensation by A’s own contribution). B’s conversion is still 88.9% taxable ($6,667), and A’s is $0. General eligibility is on the spousal Roth IRA page.
This household has a second check: only nondeductible amounts on Form 8606 Line 1 create basis, and a deducted contribution leaves Line 5 at $0 and the whole $7,500 conversion taxable. If A is covered by a workplace plan and B is not, B’s deduction phases out between $242,000 and $252,000 of joint income in 2026. If neither is covered, the IRS 2026 limits release says the phase-outs do not apply, so the contribution stays nondeductible only by electing under IRC 408(o)(2)(B)(ii) and reporting it on Line 1.
Does a community-property state merge two spouses’ IRAs for the pro rata rule?
No. IRC 408(g) is one sentence: “This section shall be applied without regard to any community property laws.” The aggregation rule sits in that same section at 408(d)(2), so a couple in any of the nine states the Form 1040 instructions list (Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, Wisconsin) still runs one calculation per titled owner.
In row 5, a $250,000 rollover IRA titled to spouse A was built from 401(k) wages earned during the marriage, so Texas law may treat part of it as B’s. The federal math ignores that: A is 97.1% taxable ($7,282) and B is at $0. If state-law ownership controlled and the IRA split evenly, each spouse would show $125,000 on Line 6 and report $7,072, or $14,144 together.
The support here is the statute’s text. Publication 590-A applies the same idea to contribution limits (“even in states with community property laws”), but Q3 found no IRS publication applying 408(g) to Line 6 by name, so a return preparer can be asked to confirm that reading for a large balance. State law can still decide who is awarded the IRA at divorce.
Can my spouse roll a pre-tax IRA into my 401(k) to clear the pro rata rule?
No. IRC 408(d)(3)(A)(ii) allows a rollover only into an eligible retirement plan “for the benefit of such individual,” meaning the IRA owner, so the spouse holding the IRA needs a plan of their own. In row 6, spouse A’s own 401(k) takes A from 96.0% taxable ($7,200) to $0, because Line 6 falls from $180,000 to $0.
Row 3 is where this blocks a household. Spouse B cannot use A’s 401(k), the same words in 408(d)(3)(A)(i) stop a rollover into A’s IRA, and 408(d)(6) allows an untaxed move between spouses only under a divorce or separation instrument. What remains for B’s $60,000 is converting it (taxable in the conversion year), a plan from B’s own future job or self-employment, or skipping B’s $7,500 contribution. For A in row 6, the question for the plan administrator is whether the plan accepts roll-ins of pre-tax IRA money and how soon the deposit posts. Plan acceptance is covered in rolling an IRA into a 401(k).
The date is each owner’s December 31. IRC 408(d)(2)(C) values the contract “as of the close of the calendar year,” and the 2025 Line 6 instructions add a note for late movers: “Don’t include an outstanding rollover from a traditional IRA to a qualified retirement plan.” Money the custodian paid out in late December 2026 and the plan deposits in January, within 60 days, therefore stays off A’s Line 6. A request the custodian has not processed by December 31 is still in the IRA’s value.
When does my spouse’s IRA become mine on Line 6?
Only at two events: a transfer under a divorce or separation instrument, or a surviving spouse’s choice to treat an inherited IRA as their own. Each one changes the receiving spouse’s December 31 balance, so a conversion at any point in that calendar year is prorated against the new amount.
Under 408(d)(6), the transferred interest is “treated as an individual retirement account of such spouse.” A $200,000 transfer in December 2026 lands on the recipient’s 2026 Line 6, making that person’s $7,500 conversion from March of that year 96.4% taxable ($7,230). The Form 8606 instructions also require a filing when a transfer “resulted in a change in the basis of the IRA of either spouse.” Sequencing is covered in Roth conversions around a divorce.
For a surviving spouse, Publication 590-B draws the line. Staying a beneficiary keeps the inherited IRA’s basis apart from your own, with separate Forms 8606 when both pay out. Treating the IRA as your own moves it onto your Line 6, and that choice is deemed made if a sole beneficiary with an unlimited right to withdraw contributes to it or skips a beneficiary RMD. IRAs inherited from anyone else stay on a separate Form 8606 for each decedent. The two-step move is on the spousal rollover then Roth conversion page.
Frequently asked questions
Does the pro rata rule change if we file married filing separately?
No. Line 6 is still each owner’s own balance. Filing separately changes other limits: the 2026 Roth contribution phase-out falls to $0 to $10,000, and the spousal IRA rule in IRC 219(c)(2)(A) requires a joint return, so a spouse without compensation has no way to make the contribution that starts a backdoor Roth that year.
Does my spouse’s 401(k) or Roth IRA count in my pro rata calculation?
No, and neither does your own. Form 8606 Line 6 counts traditional, SEP and SIMPLE IRAs, so 401(k), 403(b) and 457(b) balances stay out for both spouses. Roth IRAs stay out because IRC 408A(d)(4)(A) applies the 408(d)(2) aggregation separately to Roth IRAs and to other IRAs.
Can I give my after-tax basis to my spouse so their conversion is tax-free?
No. Basis sits on the contributor’s own Form 8606, Line 14, and carries forward only on that person’s form. In the $150,000 example, spouse A keeps $7,140 of basis and spouse B can use none of it. Basis crosses between spouses only through a 408(d)(6) transfer under a divorce or separation instrument, or at death.
If only one of us converts, do both spouses file Form 8606?
No. Only a spouse with a filing trigger files one, such as a nondeductible contribution, a conversion, or a distribution from an IRA with basis. A spouse with none files nothing, even on a joint return. A missed Form 8606 for a nondeductible contribution carries a $50 penalty, and overstating one carries $100, absent reasonable cause.
Can we still convert if our joint income is above $252,000?
Yes. The $252,000 ceiling limits direct Roth contributions, not conversions. Pub. L. 109-222, section 512, struck the old $100,000 income cap and the separate-return bar on conversions for years after 2009. Treas. Reg. 1.408A-4, A-1, still recites those limits, but current IRC 408A(c)(3) contains neither.
Method and sources. Q3 compiled primary documents and public data: IRC 408, 408A and 219, Form 8606 and its 2025 instructions, Publications 590-A and 590-B, Notice 2025-67 and Rev. Proc. 2025-32. A script ran Form 8606 line logic for each spouse to compute the tables. Couples are hypothetical. Anonymous forum anecdotes were excluded because this is a YMYL tax topic.
This article is for educational purposes only and is not individualized investment, tax, or legal advice. Consult a qualified professional about your specific situation.
