Finance · 7 min read

Mega Backdoor Roth vs Backdoor Roth IRA

A **backdoor Roth IRA** is a nondeductible traditional IRA contribution converted to Roth—works when income exceeds direct Roth limits. **Mega backdoor Roth** routes after-tax 401(k) contributions to in-plan Roth conversions, up to ~$46,000+ annually if your plan allows.

Step by step

1. Confirm plan features

Mega needs after-tax deferrals and in-service conversion.

2. Track Form 8606

Backdoor IRA needs pro-rata awareness if you hold pre-tax IRA balances.

3. Automate conversions

Mega often requires payroll coordination—HR or admin help.

Mega backdoor vs backdoor IRA

High earners with generous 401(k) plans favor mega; others use annual backdoor.

  • Backdoor Roth IRA: ~$7k/yr limit; IRA pro-rata rules.
  • Mega backdoor 401(k): Much higher ceiling; plan must allow it.

Common mistakes

  • Mega without in-service withdrawals enabled
  • Ignoring pro-rata on backdoor IRA

FAQ

Is mega backdoor legal?

Yes when plan documents and IRS rules are followed—verify with CPA.