A retirement strategy that most financial advisors never mention can let you stash up to $46,000 in a tax-free account this year.
It's called the mega backdoor Roth, and it has nothing to do with the regular Roth IRA you already know about.
Your 401(k) plan already lets you contribute up to $23,000 in 2024, or $30,500 if you're 50 or older.
But there's a second ceiling most people ignore: the total limit on all contributions to your plan, including employer matches, is $69,000 this year.
That gap between what you put in and the overall cap is where the magic happens.
If your employer's plan allows it, you can make after-tax contributions to fill that gap.
Then you convert that after-tax money into a Roth account, either inside the plan or by rolling it into a Roth IRA.
The result: years of tax-free growth on tens of thousands of dollars, far beyond the $7,000 limit on a standard Roth IRA.
The catch is that your 401(k) provider has to offer two specific features.
First, the plan must allow after-tax contributions.
Second, it must permit either in-plan Roth conversions or in-service withdrawals.
Many big employers, especially in tech, finance, and health care, quietly added these options in recent years.
Others still don't offer them, and some employees never find out their plan qualifies.
To check, log into your 401(k) account and look for a contributions section that mentions "after-tax" alongside pre-tax and Roth options.
If you don't see it, call your plan administrator and ask directly whether after-tax contributions and in-plan conversions are permitted.
The answer takes five minutes and could be worth six figures over a career.
If you convert after-tax dollars and they've already earned investment gains, those gains are taxable as ordinary income in the year of conversion.
That's why many people convert immediately, before earnings pile up, or automate the conversion with every paycheck.
Ask your plan whether it supports automatic conversions.
A second consideration is whether you need the money before retirement.
Roth conversions work best for money you can leave invested for decades.
If cash is tight, funding a regular emergency fund first still makes sense.
This strategy isn't new, but it's having a moment as more workers hit the standard contribution limits and look for somewhere else to put money.
High earners who are locked out of regular Roth IRAs because of income limits often find this is their only legal path to meaningful Roth savings through an employer plan.
Our take: the mega backdoor Roth is one of the few legitimate tax breaks still sitting in plain sight, and it rewards people who bother to read their plan documents.
If your employer offers it and you can afford the contributions, it's worth a serious look before year-end.
Final Thoughts
Just run the numbers with a tax professional first, because the conversion rules vary by plan and the tax bill on gains is real.