Quick summary
A backdoor Roth contribution is a two-step process: (1) make a nondeductible contribution to a traditional IRA, and (2) convert that money to a Roth IRA. For many higher‑income taxpayers who are barred from direct Roth contributions, this provides access to tax‑free growth and tax‑free qualified withdrawals in retirement. However, the conversion can trigger taxes if you have other pre‑tax IRA balances because of the IRS pro‑rata rule. (IRS guidance: Publication 590‑A and Form 8606.)
Why use a backdoor Roth?
- Roth IRAs grow tax‑free and qualified withdrawals are tax‑free in retirement, making them valuable for tax diversification and estate planning (IRS: Roth IRAs).
- High earners whose modified adjusted gross income (MAGI) exceeds the annual Roth contribution limits can still obtain Roth status through this workaround.
- Once inside a Roth, future earnings and qualified distributions are free of federal income tax — attractive if you expect higher future tax rates.
Source: IRS, Retirement Plans — Roth IRAs (https://www.irs.gov/retirement-plans/roth-iras).
Step‑by‑step: How to complete a backdoor Roth contribution
Follow these steps to execute a typical backdoor Roth. This is the operational checklist I use when advising clients; adapt timing based on your tax year and cash flow.
- Confirm eligibility and annual limits
- Anyone can contribute to a traditional IRA provided they have eligible compensation, but the tax deductibility of that contribution depends on income and workplace retirement coverage (IRS Publication 590‑A).
- Contribution limits change periodically. For example, the 2024 IRA limit was $7,000 with a $1,000 catch‑up for ages 50+; confirm current limits at the IRS website before contributing.
- Make a nondeductible (after‑tax) contribution to a traditional IRA
- Mark the contribution as nondeductible for your records. Use your IRA custodian’s contribution forms or online interface.
- Consider timing for the conversion
- Many advisers convert the contribution shortly after funding (days to weeks) to reduce taxable earnings in the traditional IRA. There is no mandatory waiting period, but some firms used to recommend waiting to avoid the “step transaction” risk; the IRS has not invalidated backdoor Roths when done properly and consistently.
- Convert the traditional IRA to a Roth IRA
- Instruct your custodian to convert the after‑tax contribution to a Roth IRA. If there were any earnings between the contribution and conversion, those earnings are taxable in the year of conversion.
- File Form 8606 with your tax return
- Report nondeductible contributions and conversions on IRS Form 8606. This form documents your basis (after‑tax amounts) and calculates taxable portion of conversions. Failing to file Form 8606 can cause headaches and penalties later (IRS: About Form 8606).
- Verify year‑end reporting
- Ensure your custodian issues the correct 1099‑R and that you’ve reconciled it against Form 8606. Keep records of contributions and conversion confirmations.
The most important caveat: the pro‑rata rule
If you have any other traditional, SEP, or SIMPLE IRA balances that contain pre‑tax dollars, the IRS treats all those accounts as one when calculating the taxable portion of a Roth conversion. This is the pro‑rata rule and it often surprises taxpayers.
Example (simplified):
- Traditional IRA balances at year‑end: $47,000 (pre‑tax) + $3,000 (nondeductible contribution you just made) = $50,000 total.
- If you convert the $3,000 nondeductible contribution to a Roth, the taxable portion equals the fraction of pre‑tax to total IRAs: $47,000 / $50,000 = 94% taxable. So only 6% of your conversion would be tax‑free — substantially different than the simple “no tax owed” expectation.
To avoid this, some taxpayers roll pre‑tax IRA funds into an employer plan (401(k), 403(b)) if the plan accepts rollovers. That removes pre‑tax dollars from the IRA aggregation and can make the backdoor cleaner. See our explainer on the [pro‑rata rule for backdoor Roth IRA conversions](
