Mega Backdoor Roth

How Does A Mega Backdoor Roth Work? 2024 Update!


A Mega backdoor Roth is a retirement savings strategy that could allow you to put up to $46,000 in a Roth 401(k), on top of your regular $23,000 annual contribution. There are many moving pieces that all need to fall into place in order for this strategy to work, so we highly recommend you consult a financial advisor before trying this method. Don’t let this scare you away though, since the benefits of a mega backdoor Roth are huge. If done correctly, it can potentially save you tens of thousands in taxes.

Review of 401(k) basics

Before we get into the details of a mega backdoor Roth, let’s start with some background. Many people have access to a 401(k) retirement plan. This is a plan offered through an employer and allows employees to save either pre-tax (traditional) or post-tax (Roth) money out of their paychecks each month. Many employers also offer a matching contribution to their employee’s 401(k) accounts. 401(k) accounts have limits on what the employee can add, and the total that can be contributed to the account during each tax year. 

With a 401(k), the employee can add up to $23,000 (under age 50) and $30,500 (over age 50) into their 401(k) account either on a traditional or Roth basis for 2024. On top of that, the employer can add a matching or flat contribution to the employee’s account. Pre-tax or traditional contributions are tax deductible now, and then taxable when funds are withdrawn during retirement. Many employers, but not all, offer the Roth 401(k) option in which the employee’s contributions can be made with post-tax money, and then grow tax-free. The employer match will always be traditional money and will grow tax-deferred, and taxes will be paid on those funds when they are withdrawn in retirement.

Want to know if you can make a Backdoor Roth IRA contribution? Find out here!


What is a Backdoor Roth?

Now that we have discussed the 401(k) basics, let’s talk about what the typical “Backdoor Roth” means. A Backdoor Roth IRA is a strategy used by those with income too high to contribute directly to a Roth IRA. In this instance, one would contribute to a non-deductible traditional IRA and then convert that money to a Roth IRA to allow it to grow tax-free. 

As long as there is no other money sitting in a traditional IRA that was deducted on prior tax returns, the conversion does not generally trigger a taxable event, because the money being converted was not deductible. Take a look at our blog on how to do a Backdoor Roth for a step-by-step guide.

What is a Mega Backdoor Roth?

So where does the term “Mega” come in? A mega backdoor Roth can allow up to around six times the amount you can do in a regular backdoor Roth IRA. While a backdoor Roth IRA can typically result in $7,000 of money to grow tax-free, a mega backdoor Roth can potentially result in $46,000 of money to eventually grow tax-free. That’s a lot of potential tax-free money, hence the term “mega”.

A mega backdoor Roth is done through your 401(k). In addition to your traditional or Roth 401(k) contributions (limit of $23,000 or $30,500 over age 50 for 2024), some 401(k) plans allow you to contribute to a third type of account: “after-tax” contributions. Up to $46,000 in additional “after-tax” contributions can be made in 2024 (if your employer is not providing a match; less than this if so). After-tax contributions are not tax-deductible, nor is it a Roth.

A key part of this strategy is being able to convert these after-tax 401(k) contributions to Roth. If you convert these after-tax dollars into a Roth account, you are then taking advantage of being able to grow even more tax-free money for retirement than you otherwise could. This can allow high-income earners to not only max out their Roth 401(k) and their backdoor Roth IRA, but also add significantly more to their 401(k) to potentially grow tax-free. 

In order for this strategy to work, two things need to be in place. 

First, your employer must first offer the ability to add “after-tax” contributions into the 401(k) plan. This is different from Roth 401(k) contributions. Only a handful of employers offer after-tax contributions, most of them big companies like Google, Facebook, Adobe or AT&T.

Second, the employer plan must also allow one of two things. The plan needs to allow an “in-plan Roth conversion,” where the employee’s after-tax contributions are rolled into the current Roth portion of the plan (essentially converting it to a Roth 401(k)). Or it needs to allow the employee to roll these funds out of the plan into a Roth IRA, even while still an active employee. If the employer offers after-tax contributions, but does not allow one of these two options, the mega backdoor strategy may not work. 

Are mega backdoor Roths still allowed in 2024?

Yes, mega backdoor Roths are still allowed in 20234

How much can you put in a mega backdoor Roth in 2024?

You could potentially put up to $46,000 in a mega backdoor Roth, but often it’s less than that. Here is how the maximum contribution is determined. Each year, the IRS sets employee pre-tax or Roth contribution limits, as well as maximum total limits for a 401(k) account. For 2024, the maximum combined amount that you and your employer can put into a 401(k) is $69,000 for under age 50 and $76,500 for over age 50.  

For example, if you are under age 50 and max out your Roth or traditional portion at $23,000, and your employer matched some of that into your account, let’s say $10,000 was added from your employer, you could add an additional $36,000 of after-tax contributions to this account. All combined contributions equal the $69,000 yearly maximum. If your employer didn’t match you at all, you could add $46,000 of after-tax money to your account, which will go towards your mega backdoor Roth. 

It is important not to over-contribute to a 401(k). You will need to calculate your contributions as well as the projected employer matching contributions for that year in order to do this accurately.

mega backdoor roth
Mega Backdoor Roth

Do you pay taxes on a Mega Backdoor Roth?

If you use this strategy, you will receive a 1099-R detailing the rollover/conversion. If you were able to add the money to the account and convert it quickly, there was likely no growth on the account, and no or minimal taxes will be due. However, if any of the after-tax money was invested through the year, and you do the conversion at the end of the year, the amount you earned on the contributions will likely be taxable. This all gets very complicated, so we highly recommend you use a tax professional to complete your taxes to ensure you don’t end up having a large headache on your taxes. 


Can you do both backdoor Roth and Mega Backdoor Roth in 2024?

Yes. The $7,000 yearly limit (or $7,500 if you’re over age 50) do not count against your 401(k) limits. You can use the backdoor strategy both with a non-deductible IRA and with after-tax 401(k) contributions.


Is mega backdoor Roth a good idea?

A mega backdoor Roth can be a great idea to save for retirement if you have exhausted all of your other saving accounts and you still have additional money to save. It is a good idea to talk to a fiduciary financial advisor who can help you decide what accounts are best for you to grow your retirement savings.


Who does a Mega Backdoor Roth make the most sense for?

If you are maxing out your yearly 401(k) and IRA contributions, and you still have money to save for retirement, this strategy may be a great benefit for you. It takes work and diligence, so make sure you know what you are doing. It’s always best to consult a professional so you don’t end up with a surprise tax bill at the end of the year.  Schedule a free discovery call with one of our financial planners today! 

Kayla Andrews Financial Planner

Kayla Welte, AFC®, ChFC®, CFP®, has been helping clients maximize their finances since 2009. With a background in financial education & counseling, Kayla is passionate about helping people prioritize & reach their financial goals. Kayla is a Financial Planner at District Capital Management, a financial planning firm designed to help professionals in their 30s & 40s elevate their finances. Schedule a free discovery call.


District Capital is an independent, fee-only financial planning firm. We help professionals and entrepreneurs in their 30s and 40s elevate their finances and maximize their money. We are based in Washington, D.C and we work with people virtually nationwide.

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