Mega Backdoor Roth After-Tax 401k 2027

Calculate mega backdoor Roth 2027 — after-tax 401k contributions + in-plan Roth conversion. Up to $46k/yr additional Roth. Plan support required.

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How It Works

Standard time-value-of-money calculation. Compounding annually at stated rate. Pre-tax and post-tax shown.

2027 Updates

All IRS limits indexed annually for inflation. Use most recent year. Catch-up contributions for 50+ and new 60-63 super catch-up under SECURE 2.0.

Best Practices

Max tax-advantaged accounts first (401k match → HSA → Roth IRA → 401k). Then taxable brokerage. Bonds/CDs for stable yield component.

Common Pitfalls

Forgetting employer match (free money). Holding tax-inefficient funds in taxable. Withdrawing early (penalties). Not rebalancing.

Source: irs.gov Section 415(c) total contribution limits, financialsamurai.com. Last updated: May 2026.