Backdoor Roth IRA 2026: standard $7,500 and mega $42,500+
For single filers above $168K MAGI or married filing jointly above $252K per IRS Publication 590-A Table 2-1, direct Roth contributions are off the table. The backdoor is a legal, IRS-acknowledged path under 26 U.S.C. § 408(o) (non-deductible Traditional contribution) and 26 U.S.C. § 408A(d)(3) (conversion) that gets your money into Roth anyway. The mega backdoor multiplies the capacity through your 401(k) under IRS Notice 2014-54. Last verified 2026-06-14.
Standard backdoor Roth: 5 steps
- 1
Open a Traditional IRA
If you do not already have one, open a Traditional IRA at any custodian (Vanguard, Fidelity, Schwab, E*TRADE all offer this). The account name and process are identical to a Roth IRA.
- 2
Contribute up to $7,500 non-deductible
Make a non-deductible contribution. Because you are above the income limit for the deduction, you would not get one anyway. Track it as non-deductible (this becomes your basis).
- 3
Convert to Roth immediately
Within a few days of the cash settling, convert the entire Traditional balance to your Roth IRA. Same custodian, internal transfer. Speed matters: any earnings before conversion are taxable.
- 4
File IRS Form 8606 with your tax return
Report the non-deductible contribution (Part I) and the conversion (Part II) on IRS Form 8606. Per IRS Publication 590-A, Form 8606 establishes your $7,500 basis under 26 U.S.C. § 408(o)(4) so the conversion is treated as a return of basis (zero tax) rather than a taxable distribution.
- 5
Repeat every year
The backdoor is an annual ritual. Each tax year, contribute $7,500 ($8,600 at 50+) non-deductibly and convert. Many custodians have a one-click backdoor flow.
Pro-rata rule: the trap that surprises high earners
The trap (26 U.S.C. § 408(d)(2)): the IRS treats all your Traditional, SEP, and SIMPLE IRA balances as one pool when calculating the taxable portion of any conversion, per IRS Publication 590-A "Are Distributions Taxable?" and the IRS Form 8606 Part II instructions. If you have a $92,500 pre-tax rollover IRA and you add $7,500 non-deductible plus convert that $7,500, only $563 of the conversion is tax-free. The other $6,937 is taxable as ordinary income.
Worked example
| Pre-tax Traditional IRA balance | $92,500 |
| Non-deductible contribution (basis) | $7,500 |
| Total IRA value | $100,000 |
| Pre-tax percentage | 92.50% |
| Convert $7,500 -> taxable portion | $6,937 |
| Convert $7,500 -> tax-free portion | $563 |
Workaround: roll the $92,500 pre-tax balance into a workplace 401(k) before converting. 401(k) balances are excluded from the pro-rata calculation, leaving you with only the $7,500 non-deductible basis, which converts tax-free.
Mega backdoor Roth through your 401(k)
If your employer's 401(k) plan allows after-tax contributions plus either in-plan Roth conversions or in-service withdrawals, you can move much more than $7,500 a year into Roth space. The legal foundation is IRS Notice 2014-54, which permits the after-tax 401(k) money to be separated from pre-tax money on distribution. The 2026 total 401(k) limit under 26 U.S.C. § 415(c) is $72,000 per IRS Notice 2025-67.
2026 mega backdoor capacity
| Total 401(k) limit (under 50) | $72,000 |
| Less: employee deferral max | ($24,500) |
| Less: typical employer match | ($5,000) |
| Mega backdoor headroom | ~$42,500 |
You contribute $42,500 after-tax to your 401(k), then immediately convert it to Roth (either in-plan or via in-service withdrawal to a Roth IRA). Per IRS Notice 2014-54 and 26 U.S.C. § 402(c)(2), the IRS permits the after-tax basis to be split from earnings on distribution; the basis converts tax-free. Headroom varies by plan and match generosity; check your plan documents.
Standard vs mega backdoor at a glance
| Attribute | Standard backdoor | Mega backdoor |
|---|---|---|
| 2026 capacity | $7,500 ($8,600 if 50+) | Up to ~$42,500 |
| Account used | Traditional IRA -> Roth IRA | After-tax 401(k) -> Roth 401(k) or Roth IRA |
| Eligibility | Anyone with earned income | Plan must allow after-tax + conversions |
| Pro-rata risk | Yes, across all your IRAs | No (401(k) is separate pool) |
| Tax form | Form 8606 | Form 1099-R; tracked by custodian |
Common mistakes
- Letting earnings pile up. Waiting months between contribution and conversion turns growth into taxable income. Convert within a week.
- Skipping IRS Form 8606. Without it the IRS has no record of your basis under 26 U.S.C. § 408(o)(4) and could tax the conversion. Per IRS Publication 590-A "Reporting your nondeductible contributions", file every year you contribute non-deductibly. $50 penalty per missing year under 26 U.S.C. § 6693(b).
- Ignoring pro-rata (26 U.S.C. § 408(d)(2)). Doing the backdoor with a sizeable pre-tax IRA balance creates a tax bill per IRS Form 8606 Part II. Roll the pre-tax balance into a 401(k) first (excluded from the pro-rata calculation per IRS Publication 590-A).
- Mistaking it for tax avoidance. The backdoor lets you fund a Roth despite income limits. It does not avoid tax on pre-existing pre-tax balances.