Updated 2026-03-30
Mega Backdoor Roth: The High-Earner Tax-Free Strategy
How after-tax 401(k) contributions let you shelter up to $72,000 per year in tax-free accounts
The mega backdoor Roth takes advantage of the gap between the employee deferral limit ($24,500) and the total defined contribution limit ($72,000). The difference can be filled with after-tax contributions that are then converted to Roth - tax-free.
The Three 401(k) Contribution Types
- Pre-Tax / Traditional: $24,500 limit, tax-deferred growth
- Roth: $24,500 limit (shared), after-tax in, tax-free out
- After-Tax (Non-Roth): Up to $72,000 total limit, the mega backdoor secret
Does Your Plan Support It?
You need two features: after-tax contributions AND in-plan Roth conversion (or in-service distribution). About 50% of large employer plans offer both. Check your Summary Plan Description or ask your HR department.
Step-by-Step Process
- Max out your pre-tax or Roth contributions ($24,500)
- Make after-tax contributions up to the $72,000 total limit
- Convert the after-tax amount to Roth (in-plan conversion or in-service distribution)
- Convert as soon as possible to minimize taxable growth on the after-tax contributions
Frequently Asked Questions
The maximum is the gap between your pre-tax/Roth contributions plus employer match and the $72,000 total limit. For example, if you contribute $24,500 and your employer adds $10,000 in match, you can make up to $37,500 in after-tax contributions for mega backdoor Roth conversion.
Yes. The mega backdoor Roth is fully legal and explicitly supported by IRS guidance. Congress considered eliminating it in the Build Back Better Act, but that provision was not enacted. It remains available for plans that support after-tax contributions and in-plan Roth conversions.
Pavlo Pyskunov
Managing Director & Investment Fund Director
Pavlo Pyskunov analyzes employer-sponsored retirement plans using IRS publications and DOL Form 5500 filings, helping workers maximize their 401(k) savings through data-driven guidance.
Last updated: 2026-03-30