Backdoor and Mega Backdoor Roth: How High Earners Get In
Roth accounts are the most valuable retirement vehicles available — tax-free growth and tax-free withdrawals. But Roth IRAs have income limits, and high earners are locked out of direct contributions. Two strategies solve this: the backdoor Roth and the mega backdoor Roth.
The Problem: Roth IRA Income Limits
For 2026, you can contribute directly to a Roth IRA only if your modified AGI is under the phase-out range. Above it, direct contributions are prohibited:
- Single: phase-out $153,000–$168,000
- Married filing jointly: phase-out $242,000–$252,000
There is no income limit on conversions, however — and that is the loophole both strategies exploit.
The Backdoor Roth, Step by Step
- Contribute to a Traditional IRA. There is no income limit on non-deductible Traditional IRA contributions. Contribute up to the annual limit ($7,500 for 2026, $8,600 if 50+).
- Convert it to a Roth IRA. Do the conversion promptly. Since the contribution was after-tax, there's little or no tax owed on the conversion.
- Report it correctly. File Form 8606 so the IRS knows the contribution was non-deductible. This is the step people forget and end up double-taxed.
The pro-rata rule — the critical catch
If you hold any pre-tax money in a Traditional IRA (including a rollover IRA from an old 401k), the conversion is taxed on a pro-rata basis across all your IRA balances — not just the new contribution. Someone with a large rollover IRA who converts $7,500 could owe tax on most of it.
The fix: roll any pre-tax IRA money into your employer's 401(k) before doing the backdoor conversion, leaving only after-tax basis in the IRA. Many 401(k) plans accept incoming rollovers for exactly this reason.
The Mega Backdoor Roth
The mega backdoor is far bigger — it can shelter tens of thousands of dollars a year — but it depends on your employer's plan offering two specific features:
- After-tax (non-Roth) contributions above the normal deferral limit, up to the total plan limit ($72,000 for 2026, including employer match and all employee contributions).
- In-service withdrawals or conversions that let you move that after-tax money into a Roth while still employed.
If your plan allows it, the sequence is: max out pre-tax or Roth deferrals, then contribute after-tax dollars up to the total limit, then convert those after-tax dollars to Roth (either an in-plan Roth or a Roth IRA). The result can be $30,000+ of extra Roth space per year.
Check your plan first
Not every 401(k) supports this — many don't allow after-tax contributions, and some don't allow in-service conversions. Ask your plan administrator whether both features exist. If they don't, the mega backdoor isn't available to you, and you're limited to the standard backdoor plus your regular deferrals.
Why This Matters
High earners often face the opposite tax problem from everyone else: they will likely be in a higher bracket in retirement once RMDs and Social Security stack up. For them, paying tax now (via conversion) to grow tax-free forever is a clear win. Roth money also doesn't count toward the combined-income calculation that taxes Social Security, and it isn't subject to RMDs.
Keep Good Records
Both strategies hinge on clean paperwork. Track your after-tax basis, file Form 8606 every year, and use a tax professional if your situation includes a rollover IRA or a plan that only partially supports the mega backdoor. Done correctly, these are fully legal, thoroughly documented maneuvers the IRS explicitly permits.
To see how Roth conversions fit your long-term plan, try the Roth conversion calculator or build a full projection in the planner.
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