What is the mega backdoor Roth and who can use it?

The mega backdoor Roth is a strategy that lets high earners move far more than the normal limit into Roth accounts. It works only if your 401(k) plan allows both after-tax (non-Roth) contributions and either in-plan Roth conversions or in-service withdrawals. The total 2025 limit for all contributions to a 401(k) — your deferrals, the employer match, and after-tax money — is $70,000 ($77,500 if 50+). After maxing your $23,500 and counting the match, you fill the remaining space with after-tax dollars, then promptly convert them to Roth so future growth is tax-free. Not every plan supports it, so confirm with HR or your plan documents. It's powerful for people who can save aggressively beyond standard limits. See how Roth dollars grow at wealthserene.com/tools/retirement-planner.