Backdoor Roth vs direct Roth contribution
Last updated August 2026
Short answer
The two routes reach the same destination with the same annual amount. Only the paperwork and the pro-rata exposure differ.
The direct contribution
Put up to $7,500 into a Roth IRA for 2026, or $8,600 from age 50, if your modified AGI is below the phase-out.
Nothing is reported beyond what the custodian files, and no additional form is required on your return.
Inside the phase-out range, the permitted contribution shrinks proportionally rather than disappearing at a cliff.
The backdoor sequence
Contribute to a traditional IRA without claiming a deduction, which you may do at any income.
Convert that balance to a Roth IRA. Conversions have no income limit, which is the gap the strategy uses.
File Form 8606 to record the non-deductible basis and the conversion, so the money is not taxed a second time later.
The pro-rata rule decides the cost
Conversions draw proportionally from every traditional, SEP and SIMPLE IRA you hold, not from the specific dollars you just contributed.
Somebody with a $100,000 rollover IRA and a fresh $7,500 non-deductible contribution finds roughly 93% of the conversion taxable.
Somebody with no other IRA money converts almost tax-free, since only the small earnings between contribution and conversion are taxable.
Try it in Walnut
Walnut connects to your brokerage and reads your IRA balances across accounts, which is exactly the figure the pro-rata calculation depends on.
Clearing the way
The measurement date is 31 December of the conversion year, so the balance mid-year does not settle it.
Rolling existing pre-tax IRA money into an employer 401(k) removes it from the calculation, if your plan accepts incoming rollovers.
A solo 401(k) can serve the same purpose for someone self-employed, which is a common reason to open one.
Getting the paperwork right
Form 8606 is filed for the contribution year and again for the conversion, and both matter.
Missing forms are the most common failure, and the consequence arrives years later as tax on money that was already taxed.
Keep copies permanently. Reconstructing basis from custodian statements a decade afterwards is considerably harder than filing the form at the time.
If you are inside the phase-out
Between the thresholds, a partial direct contribution is permitted and the rest can go through the backdoor.
Running both in one year is allowed and adds paperwork, so many people simply use the backdoor for the whole amount.
Income is often uncertain until the year ends, which is another argument for the backdoor: it works at any income, so there is nothing to recalculate in April.
Sources
The 2026 Roth phase-out ranges are from IRS Notice 2025-67. Conversions, the pro-rata calculation and Form 8606 basis tracking are covered in Publication 590-A and Publication 590-B. Walnut is informational and is not an investment adviser. This guide is educational and not personalized tax advice.
FAQ
What is a backdoor Roth?
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Making a non-deductible contribution to a traditional IRA and then converting it to a Roth IRA. It exists because contributions to a Roth are income-limited while conversions are not, so the two steps together reach a destination the direct route closes off.
When should I just contribute directly?
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Whenever your income allows it. For 2026 the Roth phase-out runs $153,000 to $168,000 for single filers and $242,000 to $252,000 for married filing jointly. Below those ranges the direct contribution is simpler and involves no extra forms.
What is the pro-rata rule?
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A conversion is treated as coming proportionally from all your traditional, SEP and SIMPLE IRA balances combined, not just from the money you just contributed. Existing pre-tax IRA money therefore makes part of the conversion taxable.
How do I avoid the pro-rata problem?
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Have no pre-tax IRA balances on 31 December of the conversion year. The common route is rolling existing traditional IRA money into an employer 401(k), which is excluded from the calculation, if your plan accepts incoming rollovers.
Is a backdoor Roth legal?
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It is a widely used sequence of two permitted transactions, and the IRS has never challenged it as a general matter. Congress has considered restricting it more than once, so it is worth treating as a rule that could change.
What paperwork does it require?
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Form 8606 for both the non-deductible contribution and the conversion, filed for the relevant tax years. Skipping it means losing the record that the money was already taxed, which produces a second tax bill later.
How long should I wait before converting?
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There is no statutory waiting period. Some people convert immediately, others wait a short while. Converting quickly minimises earnings, which are taxable at conversion, so speed reduces the tax rather than creating a problem.
Is there a limit on how much I can convert?
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No. Conversion amounts are unlimited and unaffected by income. The $7,500 limit applies to the contribution step, which is why the backdoor moves the same annual amount as a direct contribution would.
What if my income lands inside the phase-out?
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You can make a partial direct contribution and use the backdoor for the rest, or simply use the backdoor for the whole amount. Since income is often uncertain until the year ends, many people default to the backdoor to avoid recalculating in April.
Could this strategy be closed?
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Congress has considered restricting it more than once without doing so. It relies on two individually permitted transactions rather than on a loophole in a single rule, but anyone building a long-term plan around it should treat it as a rule that could change.