Backdoor Roth IRA: A Step-by-Step Walkthrough (2026)
How to execute high-income Roth contributions while managing tax reporting and the Pro-Rata rule.
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Backdoor Roth IRA
The step-by-step method for making Roth contributions when you earn too much to contribute directly.
Informational only
This guide explains the mechanics of the Backdoor Roth strategy and does not constitute tax or financial advice. The Pro-Rata Rule in particular requires careful evaluation of your specific IRA balances. Consult a CPA or tax professional before executing.
What this guide covers
The Backdoor Roth IRA is a two-step process that lets high earners make Roth contributions indirectly. The key numbers for 2026:
The Pro-Rata Rule: the one thing you must get right
Before executing this strategy, you need to understand the one rule that can make the entire conversion taxable. The IRS does not let you cherry-pick which IRA dollars you convert — it treats all your Traditional, SEP, and SIMPLE IRA balances as a single pool.
If you have $93,000 in a pre-tax Traditional IRA and contribute $7,000 post-tax, your total IRA pool is $100,000. Only 7% of any conversion is treated as post-tax. Converting $7,000 means $6,510 is taxable — the opposite of what you intended.
✓ Clean conversion (what you want)
Your Traditional, SEP, and SIMPLE IRA balances total $0 before you make the non-deductible contribution. Your $7,000 contribution is 100% post-tax, and the conversion triggers no additional tax.
✗ Pro-Rata problem (what to avoid)
You have any pre-tax IRA balance — including rollover IRAs from old 401(k)s. The IRS calculates the taxable portion of your conversion proportionally across all IRA funds, making the strategy largely pointless.
How to clear pre-tax IRA balances
If you have rollover or Traditional IRA balances from old jobs, you have two options:
- Roll the balance into your current employer’s 401(k). Most modern 401(k) plans accept incoming rollovers. This removes the balance from the IRA system entirely.
- Roll into a Solo 401(k) if self-employed. SEP-IRA and SIMPLE IRA balances can also be rolled out this way.
Step-by-step walkthrough (Vanguard)
The mechanics are identical at any major brokerage. This walkthrough uses Vanguard; Fidelity users will find the process nearly identical with slightly faster settlement.
Contribute to a Traditional IRA — non-deductible. Navigate to your Traditional IRA and contribute $7,000 (or $8,000 if 50+). When asked about deductibility, select non-deductible. This is a post-tax contribution — you get no tax break now, but you won’t be taxed again on withdrawal.
Wait for settlement (2–3 business days). The funds land in a money market settlement account first. Do not buy securities during this window. Any gains — even $0.12 in interest — create a small taxable amount at conversion. Waiting keeps the math clean.
Convert to Roth IRA. Find the “Convert to Roth IRA” option (on Vanguard: Transact → Convert to Roth IRA). Transfer the entire balance. When asked about tax withholding, select 0% — do not withhold taxes. Withholding reduces the amount converted and creates a taxable event.
Invest the converted funds. Once the conversion settles in your Roth IRA (usually same-day), allocate to your target index funds or ETFs. You’re done.
Tax reporting: Form 8606
Every year you execute a Backdoor Roth, you must file IRS Form 8606 with your tax return. This is non-negotiable — it’s the mechanism that prevents the IRS from taxing your conversion again at withdrawal.
Part I — Non-deductible contributions
You report the non-deductible Traditional IRA contribution here. This establishes your “basis” — the post-tax amount that won’t be taxed again. If you skip this form, the IRS has no record of your basis and may tax the entire conversion.
Part II — Roth conversions
You report the conversion amount here. Because your basis equals the conversion (clean $0 pre-tax IRA scenario), the taxable amount should be $0 — or a small number if you earned interest during settlement.
Store copies of every Form 8606 you ever file. They document your cumulative IRA basis. If records are ever lost or disputed, the form is your proof that you already paid tax on those funds.
Common mistakes
Forgetting to check IRA balances first
The most common error. People execute the conversion without realizing an old rollover IRA exists — often from a 401(k) at a job held years earlier. Check all IRA accounts at all brokerages before contributing.
Withholding taxes from the conversion
If you withhold 10% from a $7,000 conversion, only $6,300 ends up in your Roth. The $700 withheld is treated as a distribution — potentially subject to the 10% early withdrawal penalty if you’re under 59½, plus income tax.
Buying securities before converting
If you invest the Traditional IRA funds and they gain value before conversion, the gain is taxable at conversion. Keep the funds in cash (settlement/money market) during the brief window between contribution and conversion.
Not filing Form 8606
Without this form, the IRS treats your entire conversion as taxable. The penalty for not filing Form 8606 is $50, and the cost of failing to document your basis compounds every year you skip it.
Annual Backdoor Roth checklist
Backdoor Roth execution checklist
📚 Citing This Guide
When referencing this content, please cite: "Backdoor Roth IRA" by jason.guide
📚 Citing This Guide
When referencing this content, please cite: "Backdoor Roth IRA: A Step-by-Step Walkthrough (2026)" by jason.guide