
The Backdoor Roth 401k is a clever way to contribute to a Roth 401k, even if your employer doesn't offer one. This strategy allows you to make after-tax contributions to a traditional 401k and then convert them to a Roth 401k.
You can make up to $19,500 in annual contributions to a traditional 401k, and an additional $6,500 if you're 50 or older. By contributing to a traditional 401k, you can take advantage of tax deductions on your contributions.
The key to a successful Backdoor Roth 401k is to make sure you're not exceeding the annual contribution limits. If you do, you may face penalties and taxes on the excess contributions.
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What is a Backdoor Roth 401k?
A Backdoor Roth 401k is a strategy that allows high-income earners to contribute to a Roth IRA, which is typically limited to those with lower incomes.
It's a clever way to save for retirement, especially for those who earn too much to contribute directly to a Roth IRA.
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To qualify for a Backdoor Roth 401k, you need to have a traditional 401k or 403b plan at work, which is a common requirement for many employees.
The key is to contribute to the traditional 401k plan, then convert those contributions to a Roth IRA in a later year.
You can't contribute more than $19,500 to a 401k plan in a single year, but that's okay, because you can still convert those contributions to a Roth IRA later.
In fact, the IRS allows you to convert up to $6,000 from a traditional IRA to a Roth IRA in a single year, but you'll need to meet certain income limits to qualify.
The income limits for Roth IRA conversions are $100,000 for single filers and $198,000 for joint filers, so make sure you're under those limits to take advantage of this strategy.
By contributing to a traditional 401k plan and then converting those contributions to a Roth IRA, you can take advantage of the tax-free growth and withdrawals of a Roth IRA.
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Benefits and Advantages
The mega backdoor Roth 401(k) strategy can help high-income earners maximize their retirement savings. This is because it allows for contributions far beyond traditional limits, up to $69,000 in 2021.
With a mega backdoor Roth 401(k), you can take advantage of tax-free growth, meaning your investments grow without being taxed. This is a huge benefit, especially for those with long-term investment goals.
One of the key benefits of a mega backdoor Roth 401(k) is flexibility. You can convert your after-tax contributions to a Roth IRA, giving you more control over your investment strategy. This flexibility is a major advantage over traditional retirement savings options.
Here are some of the key benefits of a mega backdoor Roth 401(k) at a glance:
- Maximizes Roth contributions
- Tax-free growth
- Flexibility in investment strategy
By combining after-tax contributions with a Roth 401(k) that allows after-tax Roth conversions, you can close the gap in your retirement savings. This is a powerful strategy that can help you achieve your long-term financial goals.
Advantages

The Mega Backdoor Roth Strategy offers several advantages that can help you save for retirement.
Maximizing your Roth contributions is a key benefit of this strategy, allowing high-income earners to contribute far more than traditional limits would allow, up to $69,000 annually in 2021.
With tax-free growth, your future earnings will grow without being subject to taxes, which can add up to significant savings over time.
Flexibility is another advantage of this strategy, offering the option to convert your contributions either within the 401(k) plan or to a separate Roth IRA, giving you more control over your investment strategy.
By combining after-tax contributions and a Roth 401(k) plan, you can take full advantage of the annual addition limit and close the 401(k) savings gap.
Here's a breakdown of how this works:
- Making after-tax contributions
- Converting those contributions, plus earnings, to a Roth 401(k)
Future earnings are tax-free, if you meet the Roth distribution rules.
Employer Match Reduces DC Gap
An employer match can significantly reduce the gap in contributions to a DC plan.
The match can be substantial, but there's still room for more DC contributions.
If a participant wants to contribute another $10,000, they can make the additional contribution on an after-tax basis.
They can then convert their after-tax contributions, plus any earnings, to a Roth 401(k) plan account.
All future withdrawals from their Roth 401(k) account would be tax-free.
Participants over age 50 can contribute an additional $6,500 in catch-up contributions.
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How it Works
The mega backdoor Roth 401(k) is a strategy that allows you to make after-tax contributions beyond the standard employee contribution limits.
For 2024, the pretax or Roth 401(k) deferral limit is $23,000, plus an extra $7,500 for savers aged 50 and older. This limit is part of the overall $69,000 401(k) limit for 2024.
Not all 401(k) plans allow this strategy. At the end of 2023, only about 11% of 401(k) plans permitted mega backdoor Roth conversions, according to data from Fidelity Investments.
To implement this strategy, you have two main options: In-Plan Roth Conversion or Rollover to a Roth IRA.
Here are the steps for each option:
- In-Plan Roth Conversion: Convert the after-tax contributions to a Roth 401(k) within the same plan, if your employer allows it.
- Rollover to a Roth IRA: Alternatively, roll the after-tax contributions into a Roth IRA.
The contributions themselves won’t be subject to tax again because you already paid taxes when you contributed.
Tax Implications
You'll face immediate tax consequences when converting pre-tax contributions to a Roth 401(k), but the benefit is tax-free withdrawals in retirement.
The amount you owe in taxes will be equal to the pre-tax contributions you're converting, so if you've contributed $23,000 to your traditional 401(k), you'll owe taxes on that amount when you convert it to a Roth.
The tax-free withdrawals in retirement can be a significant advantage, especially if you expect to be in a higher tax bracket during retirement.
Here's a comparison of the tax implications of the backdoor Roth 401(k) and the mega backdoor Roth 401(k):
With the mega backdoor Roth 401(k), you won't owe taxes on the conversion itself, but you will owe taxes on any earnings. This means it's often best to convert as soon as possible to minimize any earnings and associated tax liabilities.
The IRS limits how much 401(k) participants can save, and nondiscrimination requirements may impose further caps. For some, these constraints make achieving retirement readiness harder.
The mega backdoor Roth 401(k) allows participants to put potentially thousands more dollars into their 401(k) plan—and qualify for tax-free withdrawals.
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Limitations and Criticisms
A mega backdoor Roth 401(k) conversion might not be the right fit for everyone. This complex strategy requires careful consideration of several factors.
Not everyone can make a conversion under their current employer's plan. The ability to convert depends on the specific plan rules.
The size of your retirement nest egg plays a significant role in determining whether a conversion makes sense. A larger nest egg can provide more opportunities for growth.
The potential tax implications of a conversion should also be taken into account. You'll need to consider your current tax rate and how it may change in the future.
Here are some key factors to consider:
- Ability to convert under current employer's plan
- Size of retirement nest egg
- Potential tax implications
- Current versus future tax rate
Legislation and Requirements
Only about 11% of 401(k) plans permitted mega backdoor Roth conversions as of the end of 2023, according to data from Fidelity Investments.
Before making after-tax contributions, experts recommend reviewing your 401(k) documents to understand your plan's features and restrictions.
To make after-tax contributions, you must have already maxed out your pretax 401(k) contributions, which for 2024 is $23,000, plus an extra $7,500 for savers aged 50 and older.
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Proposed Legislation

The Biden administration's Build Back Better Act was a proposed piece of legislation that aimed to limit the use of designated Roth 401(k) accounts and Roth IRAs by high-income taxpayers.
It would have prohibited the rollover of after-tax 401(k) contributions to a designated Roth 401(k) account or Roth IRA, but allowed rollovers of after-tax contributions and untaxed earnings that would be taxed on transfer.
The proposed legislation also included changes to required minimum distributions and tax-reporting obligations for plan administrators, making it a complex and far-reaching piece of legislation.
The Build Back Better Act failed to pass, but some of its provisions were incorporated into the Inflation Reduction Act, which did pass, but did not address backdoor conversions.
Plan Conversion Requirements
To accomplish a Mega-backdoor Roth conversion, your 401(k) plan must allow after-tax contributions, contain a Roth 401(k) option or allow in-service distributions, and not rely on the safe harbor under the non-discrimination rules.
Many employers don't include these provisions in their plans due to added complexity and recordkeeping required. They may also lose the top-heavy plan exemption, which is a consequence of permitting after-tax contributions.
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Discrimination Testing
Discrimination testing is a crucial aspect of retirement plan administration.
In the case of a mega backdoor Roth 401(k), after-tax contributions and any matching contributions are included in the plan's actual contribution percentage (ACP) test.
Offering a mega backdoor Roth feature may make it more difficult for your plan to pass the ACP test if mostly highly compensated employees (HCEs) make after-tax contributions.
If your plan fails the ACP test, after-tax contributions and earnings must be returned to certain HCEs.
Before adopting a mega backdoor Roth 401(k), your plan consultant should perform projected testing to get an estimate of the maximum after-tax contributions allowed before a plan fails ACP testing.
Depending on the results, it may be advisable to cap contributions in the first year.
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Implementation and Strategy
Implementing a backdoor Roth 401(k) involves contributing to a traditional 401(k), converting to a Roth 401(k), paying taxes on the conversion, and monitoring for compliance with IRS rules.
To initiate the conversion process, check if your employer offers in-plan conversions, and if so, follow the necessary steps. Alternatively, you can roll over the funds to a Roth IRA. Be prepared to pay income taxes on the amount converted.
If your employer offers after-tax contributions and in-plan Roth conversions, consider implementing a mega backdoor Roth 401(k). This involves contributing after-tax dollars up to the overall 401(k) contribution limit, converting the funds to a Roth 401(k), and paying taxes on earnings.
To avoid costly mistakes, work with a financial advisor who can guide you through the process.
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Implementing a Retirement Plan
To implement a retirement plan, you need to contribute to a Traditional 401(k), making pre-tax contributions up to the allowable limit. This is the foundation of a backdoor Roth 401(k) strategy.
The IRS limits how much 401(k) participants can save, and nondiscrimination requirements may impose further caps. For some, these constraints make achieving retirement readiness harder.
You can convert your pre-tax contributions to a Roth 401(k) if your employer offers in-plan conversions. Alternatively, you can roll over the funds to a Roth IRA.
Paying taxes on the conversion is a crucial step, as you'll need to be prepared to pay income taxes on the amount converted. This can be a significant expense, but it's a necessary one if you want to take advantage of the tax-free withdrawals.
To ensure compliance with IRS rules, particularly the Prohibited Transaction Rule, you'll need to monitor your conversion process closely. This involves verifying that your conversion complies with all applicable regulations.
Here's a summary of the steps involved in implementing a backdoor Roth 401(k):
- Contribute to a Traditional 401(k): Make pre-tax contributions up to the allowable limit.
- Convert to a Roth 401(k): If your employer offers in-plan conversions, initiate the process to convert your pre-tax contributions to a Roth 401(k). Alternatively, roll over the funds to a Roth IRA.
- PAY Taxes on the Conversion: Be prepared to pay income taxes on the amount converted.
- Monitor for Compliance: Ensure that your conversion complies with IRS rules, particularly the Prohibited Transaction Rule.
Consider speaking with a financial or benefits professional about how a mega backdoor Roth 401(k) can help your employees optimize the tax treatment of their retirement savings. This can be a valuable resource in achieving retirement readiness.
Factors to Consider

When considering implementing the mega backdoor Roth strategy, there are several key factors to keep in mind.
High-income earners who are ineligible for direct Roth IRA contributions may benefit from this strategy, especially if they have a large income gap between their current and expected retirement tax brackets.
Employer plan options can greatly impact the feasibility of the mega backdoor Roth. Not all 401(k) plans allow after-tax contributions or in-plan conversions, so it's essential to check your plan's rules before moving forward.
Taxes can be a significant consideration when implementing the mega backdoor Roth. If you expect to be in a higher tax bracket during retirement, getting more money into a Roth account can be advantageous, but be prepared for the tax hit when converting pre-tax dollars.
Here are some key factors to consider when evaluating your employer's plan options:
- After-tax contributions: Can you contribute more money after taxes into your 401(k) plan?
- In-plan conversions: Can you convert your pre-tax dollars to a Roth account within your 401(k) plan?
Tool
The Mega Backdoor Roth 401(k) is a powerful tool for high-income earners looking to maximize their retirement contributions.

This strategy allows individuals to contribute significantly more to their Roth accounts than standard contribution limits permit.
It's a game-changer for those who want to save more for retirement without breaking the bank.
The Mega Backdoor Roth 401(k) blows the standard backdoor Roth 401(k) wide open, giving high-income earners a unique opportunity to supercharge their savings.
By utilizing this strategy, individuals can make the most of their income and secure a more comfortable financial future.
Examples and Real-World Scenarios
Let's take a look at some real-world examples of how the backdoor Roth 401(k) strategy can help high-income earners save more for retirement. A plan with a 5% dollar-for-dollar employer match can contribute up to $24,500 to a participant's account, leaving a gap of $58,000.
To illustrate these concepts, let's consider two hypothetical cases. Sarah, a 45-year-old high-income earner, contributes $23,000 to her traditional 401(k) in pre-tax dollars and then performs a backdoor Roth conversion, converting the funds to a Roth 401(k) and paying taxes on the $23,000.
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A key benefit of the backdoor Roth 401(k) is tax-free growth, but contributions are limited by the annual employee cap. John, a 52-year-old executive, contributes $30,500 in pre-tax dollars and an additional $36,500 in after-tax dollars, bringing his total contributions to $66,000.
Here's a breakdown of the contributions made by John and Sarah:
Tags
Backdoor Roth 401(k) is a popular strategy for high-income earners who want to contribute to a Roth 401(k) account.
You can contribute up to $20,500 per year to a 401(k) account, and an additional $6,500 if you're 50 or older.
The backdoor Roth 401(k) strategy involves contributing to a traditional 401(k) and then converting it to a Roth 401(k) account.
This strategy can help you save for retirement while avoiding taxes on the growth of your investments.
The backdoor Roth 401(k) strategy is not suitable for everyone, especially those who may be subject to the 10% penalty for early withdrawals.
You'll need to check with your employer to see if they offer a 401(k) plan and if it allows for Roth contributions.
The backdoor Roth 401(k) strategy can help you save for retirement and reduce your tax liability in the long run.
You can also use a solo 401(k) plan if you're self-employed or have a small business.
It's essential to consult with a financial advisor to determine if the backdoor Roth 401(k) strategy is right for you.
You'll need to consider your income, tax situation, and retirement goals before implementing this strategy.
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Frequently Asked Questions
Is Backdoor Roth still allowed in 2024?
Yes, the backdoor Roth IRA is still allowed in 2024, allowing eligible individuals to make non-deductible contributions to a traditional IRA and then convert to a Roth IRA.
What is the maximum 401k contribution for backdoor Roth?
For 2024, the maximum 401(k) contribution for a backdoor Roth is $69,000, or $76,500 for those 50 and older. This is in addition to the regular 401(k) contribution limit of $23,000 or $30,500 for those 50 and older.
What is the difference between a Roth 401k and a mega backdoor Roth 401k?
A Mega Backdoor Roth 401(k) allows for larger contributions than a traditional Roth 401(k), enabling you to save more for retirement tax-free. This is achieved by converting after-tax 401(k) contributions to a Roth account
What is the difference between backdoor Roth and mega backdoor Roth?
The backdoor Roth is for those who exceed the direct contribution limit, while the mega-backdoor is for those who surpass the annual 401(k) contribution limit of $20,500.
How to avoid pro rata rule for mega backdoor Roth?
To avoid the pro rata rule, roll your IRA into an employer plan or convert it to a Roth IRA by December 31st of the year you perform the Backdoor Roth. This ensures your Roth conversion is tax-free and not subject to the pro rata rule.
Sources
- https://www.investopedia.com/mega-backdoor-roth-401-k-conversion-5210877
- https://retirement.johnhancock.com/us/en/viewpoints/plan-design/can-retirement-plan-participants-do-mega-backdoor-roth-401-k--ev
- https://www.northerntrust.com/united-states/institute/articles/mega-backdoor-roth-conversions
- https://www.cnbc.com/2024/05/31/mega-backdoor-roth-conversions.html
- https://addishill.com/backdoor-roth-401k-vs-mega-backdoor-roth-401k-a-comprehensive-guide-for-high-income-earners/
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