High earners have a powerful retirement savings tool at their disposal: the mega backdoor Roth. This strategy lets you contribute up to $72,000 annually into a Roth account, far exceeding the standard 401(k) limit of $23,500 for 2024.
Here's how it works. You make after-tax contributions to your employer's 401(k) plan beyond the regular contribution limit. Your employer then allows you to convert these after-tax dollars into a Roth IRA or a Roth 401(k) component. The money grows tax-free, and withdrawals in retirement are tax-free too.
The $72,000 figure comes from the total 401(k) contribution limit of $69,000 in 2024, plus an additional $3,500 catch-up contribution if you're 50 or older. Once you've used your regular employee deferrals and employer match, the remaining space becomes available for after-tax contributions. You can then convert these to Roth status.
The appeal is obvious for high earners. Traditional IRAs cap contributions at $7,000 annually. A backdoor Roth, the basic version, lets you convert that same $7,000. The mega backdoor Roth multiplies this strategy by roughly 10 times, creating massive tax-free retirement savings potential.
Not every employer plan permits mega backdoor Roths. You must check your plan documents or ask your HR department if your 401(k) allows after-tax contributions and in-plan Roth conversions. Many plans don't offer this feature, particularly smaller companies.
Timing matters too. If your plan allows it, contribute early in the year to maximize the time your money sits in the tax-free Roth account. The pro-rata rule can complicate things