# Mega Backdoor Roth

*Retirement & Benefits — Finicade finance glossary*

A mega backdoor Roth uses after-tax 401(k) contributions above the normal deferral limit, then converts them to Roth — tens of thousands more sheltered.

A mega backdoor Roth uses after-tax 401(k) contributions above the normal deferral limit, then converts them to Roth — potentially sheltering tens of thousands more per year. It only works if your plan permits both after-tax contributions and in-service conversions, which most don't. Where available it's the largest tax-free savings opportunity in the US system, and worth asking your plan administrator about explicitly.

**Also known as:** mega backdoor, after-tax 401k conversion

**Related terms:** [Backdoor Roth IRA](https://finicade.com/glossary/backdoor-roth-ira), [401(k)](https://finicade.com/glossary/401k), [Contribution Limit](https://finicade.com/glossary/contribution-limit), [Roth IRA](https://finicade.com/glossary/roth-ira), [Solo 401(k)](https://finicade.com/glossary/solo-401k)

Source: https://finicade.com/glossary/mega-backdoor-roth