Backdoor Roth IRA for High Income: A Year-End Planning Guide

A backdoor Roth IRA is a two-step move for earners above the Roth income limit: make a nondeductible contribution to a traditional IRA (up to $7,500 for 2026, or $8,600 if you’re 50 or older), convert it to a Roth IRA, and report both on Form 8606. It stays open at any income.

• Who needs it: direct Roth IRA contributions start shrinking at $153,000 of modified adjusted gross income for single filers and $242,000 filing jointly, and stop entirely at $168,000 and $252,000.
• When it’s close to tax-free: only when you hold no other pre-tax IRA money, because the pro-rata rule taxes the conversion in proportion to all your IRAs.

Most high earners already know backdoor Roths exist. Where it goes wrong is the order of the two steps, or the month they happen in.

How does a backdoor Roth work, step by step?

1. Contribute after-tax money to a traditional IRA. Make it nondeductible on purpose. There’s no income limit on this step.
2. Convert that contribution from the traditional IRA into a Roth IRA. Conversions carry no income cap at all.
3. File IRS Form 8606 for the year of the contribution, to put your after-tax basis on record.

The mechanics are simple. What decides your tax bill is what else is sitting in your IRAs, and how much time passes between steps one and two.

How do you fund a Roth IRA when you’re over the income limit?

The strategy carries no income limit, because you’re not making a direct Roth contribution.

• You make a nondeductible contribution to a traditional IRA, which anyone with earned income can do.
• Then you convert that contribution to a Roth.
• Keep it nondeductible on purpose: you don’t want a tax deduction working against you later.

For 2026, you can contribute up to $7,500 to a traditional IRA, or $8,600 if you’re 50 or older.

Will the pro-rata rule make your conversion taxable?

Whether the conversion comes out nearly tax-free depends on what else is sitting in your IRAs, not on the contribution you just made.

How the pro-rata rule pools your IRAs

The IRS doesn’t look at your new contribution in isolation. Under the pro-rata rule, it pools every traditional, SEP, and SIMPLE IRA you own into one combined balance. Your conversion is taxed in proportion to the pre-tax share of that whole pool.

Workplace plans don’t count toward this pool. A 401(k) or 403(b) stays separate.

Clear pre-tax balances before you convert

The usual culprits:

• Old rollover IRAs
• Forgotten SEP or SIMPLE accounts
• Any traditional IRA contribution you deducted in past years

Clear them out, typically by rolling that pre-tax money into a current employer’s 401(k) if the plan accepts incoming rollovers. Your combined IRA balance then goes back to just the nondeductible contribution you’re about to convert.

When should you convert?

Once the contribution is in, the timing of the conversion and the rest of your year’s income decide the tax bill.

Convert before the money grows

Any gain the contribution earns before you convert becomes taxable at conversion. Convert soon after contributing, and keep the money in cash rather than invested until you do, so the taxable amount stays close to zero.

Time the taxable portion before year-end

Whatever portion of the conversion is taxable stacks on top of your household’s other income for the year: salary, bonuses, capital gains, and anything else in your bracket.

• Better windows: a lower-income year, a sabbatical, or a gap between jobs is a better time to convert an old pre-tax balance.
• Worse windows: a year when your income is already stretched.

File Form 8606 so you’re not taxed twice

Form 8606 reports your nondeductible contribution and establishes basis in the IRS’s records: the proof that you already paid tax on that money once.

• Skip it, and the IRS has no record that your contribution wasn’t pre-tax. The same dollars risk being taxed twice: once when you contributed, again when you withdraw.
• File it for the tax year of the contribution, and complete both the contribution and the conversion by December 31 if you want the whole sequence to count cleanly for this year’s return.

How do you report a backdoor Roth on Form 8606?

Your custodian sends a Form 1099-R for the conversion. Form 8606 turns it into a taxable and a tax-free amount:

1. Line 1: the nondeductible contribution you made for the year.
2. Line 2: your basis from earlier years, which is last year’s line 14.
3. Line 6: the December 31 value of all your traditional, SEP, and SIMPLE IRAs, plus any outstanding rollovers.
4. Line 8: the amount you converted to Roth.
5. Lines 9 to 11: the form divides your basis by your year-end balance plus the conversion, then applies that share to the conversion to find the tax-free part.
6. Part II, lines 16 to 18: the conversion repeats on line 16, the tax-free part moves to line 17, and the taxable amount lands on line 18, which flows to Form 1040 line 4b.
7. Line 14: the basis you carry into next year. Keep every Form 8606 you file, since that basis follows you until it is used.

Here is the $95,000 rollover example from above on the form, next to the same year with the rollover moved into a 401(k) before December 31:

With the rollover IRA in place, $6,951 of the $7,500 conversion is taxable. The unused basis is not lost: it carries forward on line 14 to later conversions or withdrawals.

What tax traps should you watch for?

• The pro-rata rule: your conversion is taxed in proportion to the pre-tax share of all your traditional, SEP, and SIMPLE IRAs combined, not just the account you just contributed to.
• Pre-conversion growth: any gain your contribution earns before you convert is taxable, so converting quickly keeps the number near zero.
• No impact from 401(k)s: workplace retirement plans sit outside the pro-rata pool entirely, and can even be used to absorb pre-tax IRA money before you convert.

How Nino keeps your backdoor Roth coordinated

• A CPA usually sees your return after the year has already closed.
• A financial advisor usually sees your portfolio, not your payroll or a spouse’s income.

Neither one is positioned to catch a stray pre-tax balance in October, while there’s still time to clear it before December 31.

Nino’s Advisor plans put a financial planner and a CPA on the same household picture, year-round. That’s what it takes to sequence a backdoor Roth correctly: someone has to see the contribution, the pro-rata math, and the conversion together, before the deadline, not after.

See current plans on the pricing page, or how Nino compares to other options, and confirm who’s watching your backdoor Roth timing before this December 31.