Solo 401k Backdoor Roth: A Comprehensive Guide

A Solo 401k backdoor Roth is a great way to save for retirement, but it can be a bit confusing.

The Solo 401k backdoor Roth is a strategy that allows you to contribute to a traditional Solo 401k and then convert those funds to a Roth IRA.

To qualify for a Solo 401k, you must be a self-employed individual or have a small business with no full-time employees.

You can contribute up to 20% of your net earnings from self-employment to a Solo 401k, and an additional $19,500 in 2022 if you're under 50 years old.

To implement the solo 401k backdoor Roth strategy, you'll need to understand the mechanics involved. A solo 401k plan must allow after-tax contributions and in-service distributions to make this strategy work.

You'll need to make after-tax contributions to your solo 401k plan, which will be used to fund your Roth account. This is typically done by opening a separate bank account for the after-tax funds and immediately rolling them into a Roth bank account under the plan.

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The solo 401k plan provider must allow after-tax contributions, in-service distributions, and have an integrated investment platform. This is usually offered by paid solo 401k plan providers, and you can compare them to find the best fit for your needs.

Here's a summary of the three bank accounts typically involved in a plan doing a Mega Backdoor Roth:

To determine how much you can contribute, you'll need to consider your earned income, which is your net Schedule C income or W-2 income. You can only contribute up to the amount you earn, minus social security and Medicare taxes.

A solo 401k plan can be a bit complex, but let's break it down to the basics. The solo 401k contribution limit in 2024 is $69,000, or $76,500 if you're 50 years of age or older.

You can contribute to a solo 401k plan as both the employer and the employee, and you can choose whether to contribute to a traditional solo 401k account or a Roth solo 401k account.

In a traditional solo 401k account, you contribute with pre-tax income, which means the money you contribute gets deducted from your income tax. You get a tax break now, but you pay taxes on withdrawals in retirement.

In a Roth solo 401k account, you contribute with after-tax income, which means the money you contribute is not deducted from your income tax. You don't get a tax break today, but you pay zero taxes on withdrawals in retirement.

Here's how employee and employer contributions work:

To maximize your contributions, you can put away a maximum of $23,000 ($30,500 if you're over 50) into your Roth solo 401k account for 2024, and then contribute the rest with employer compensation calculated at 25% of income.

To execute the mega backdoor Roth strategy, you'll need to understand the mechanics involved. A solo 401k plan must allow after-tax contributions and in-service distributions.

The strategy requires three key elements: a solo 401k plan provider that allows after-tax contributions, a plan provider that allows in-service distributions, and sufficient earned income to make the after-tax contribution. You'll also need to make enough money for this strategy to make sense.

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You can contribute up to 100% of your income up to a maximum of $23,000 ($30,500 if you're at least 50 years of age) for 2024 as an employee. Employers can contribute up to 25% of their income, but only to a traditional pre-tax account.

To implement the mega backdoor Roth strategy, you'll need to make after-tax contributions to your solo 401k plan. This can be done by rolling over after-tax funds into a Roth bank account under the plan. It's recommended to open a separate bank account for the after-tax funds and a separate Roth bank account for simplicity.

Here's a breakdown of the typical bank accounts under a plan doing a mega backdoor Roth:

After-tax contributions are not considered employee deferral or employer profit-sharing contributions and are not subject to the 401k plan triggering rules. This means you can roll over after-tax 401k funds to a Roth IRA, even if you're under 59 1/2.

The after-tax contribution limit is tied to your earned income, which means you can only contribute up to the amount you earn. For example, if you made $70,000 of net Schedule C income, you could do an after-tax contribution of around $64,000 in 2025, taking into account social security and FICA taxes.

Once the after-tax funds are converted to Roth, you can take a distribution without satisfying the five-year rule since the conversion came from after-tax funds.

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To be eligible for a Solo 401(k) plan, your business must not have any non-owner employees who work over 1000 hours.

The Solo 401(k) plan contribution rules are governed by the Internal Revenue Code, which sets limits on how much you can contribute each year. Employee deferral contributions can be made in pretax or Roth, up to $23,500 or $31,000 for individuals at least age 50.

As a self-employed individual, you can contribute a portion of your income to the plan as an employer profit sharing contribution, up to 20% of your compensation or $14,000, whichever is less.

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To be eligible for a Solo 401(k) plan, your business must not have any non-owner employees working over 1000 hours. This means you can have employees who work under 1000 hours, but no one who works full-time as a non-owner.

The Solo 401(k) is designed for self-employed individuals and small business owners, making it a popular choice for entrepreneurs. The plan is similar to a traditional 401(k) but covers only the owner and/or spouse.

To qualify, your business must not have any non-owner, full-time employees. This allows you and your spouse to establish a Solo 401(k) plan for your business.

Additional reading: Penalty for Employer Not Paying 401k

Contributions to a Solo 401(k) plan can be made in pretax or Roth, but only if the plan document permits.

Employee deferral contributions are made dollar for dollar and are not based on a percentage of income. The per individual limit for employee deferral contributions in 2025 is $23,500 or $31,000 for individuals at least age 50.

Employer profit sharing contributions can be made in an amount up to 25% of the participant's self-employment compensation, but only 20% in the case of a sole proprietorship or single member LLC. These contributions must be made in pretax.

The aggregate limit for employee and employer contributions cannot exceed $70,000 or $77,500 if at least 50 for 2025.

A self-employed individual under the age of 50 who makes $70,000 of income would be able to contribute $23,000 as an employee deferral and $14,000 as a pretax employer profit sharing contribution, providing an aggregate plan contribution of $37,500.

For more insights, see: 401k Balance at 50

The tax implications of a Solo 401k backdoor Roth strategy are complex, but don't worry, I've got you covered. Any gains in your account are subject to taxes, so it's essential to transfer from an after-tax account into a Roth immediately.

The proposed changes to the tax code could significantly impact Solo 401k plans, which have offered flexible contribution limits and tax benefits. For small business owners and self-employed individuals, adapting to a potentially reduced ability to make after-tax contributions might mean seeking alternative investment strategies or adjusting to increased tax burdens sooner than anticipated.

The current tax rules allow for employee deferral contributions of up to $23,500 or $31,000 for individuals at least age 50 in 2025. Employee deferral contributions can be made in pretax or Roth, if the plan document permits.

A self-employed individual under the age of 50 who makes $70,000 of income can contribute $23,000 as an employee deferral, in pretax or Roth, and 20% of their compensation or $14,000 as a pretax employer profit sharing contribution, providing them with an aggregate plan contribution of $37,500.

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To get started with the solo 401k backdoor Roth strategy, you'll need a solo 401k plan provider that allows after-tax contributions and in-service distributions. Not all providers offer these options, so be sure to check.

To qualify for this strategy, you'll also need to make enough money to make it worthwhile. The article suggests comparing solo 401k plan providers to find one that meets your needs.

Here are the key points to keep in mind:

Carry's Solo 401k Plan is an option to consider, as it offers an integrated investment platform, no-fee robo-advisor, and full support with compliance and plan administration.

You can transfer your after-tax contributions into a Roth account in two different ways. There are two different ways that the after-tax contributions are moved into a Roth account.

You can rollover your funds into a Roth IRA, which is a tax-free transfer because you contributed with after-tax dollars. The IRS doesn’t require you to pay any taxes on conversions to a Roth account.

An in-plan conversion is another option, allowing you to transfer your funds directly into your Roth solo 401k account. Both transfers are tax-free, which is a major advantage of the solo 401k backdoor Roth strategy.

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IRA options can be overwhelming, but let's break it down. A 401(k) and Backdoor Roth IRA are two lesser-known strategies that can offer immense potential for self-employed individuals and small business owners to maximize their retirement savings.

Traditional IRAs, 401(k)s, and Roth IRAs are just the tip of the iceberg. The Solo 401(k) and Backdoor Roth IRA are two alternatives worth exploring.

A Solo 401(k) and SEP IRA are two options that may be better suited for self-employed individuals. However, it's essential to choose the one that aligns with your financial goals.

The Backdoor Roth IRA strategy allows high-income earners to circumvent income limits on Roth IRA contributions. This is achieved by making a non-deductible contribution to a Traditional IRA and then converting that to a Roth IRA.

High-income individuals can also use the Mega Backdoor Roth strategy to make large after-tax contributions to a 401(k) plan and then convert these to a Roth IRA or Roth 401(k).

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These strategies have been crucial in democratizing access to Roth accounts for high-income individuals and small business owners. They allow those who would otherwise be barred by IRS income restrictions to benefit from Roth accounts.

Here's a brief comparison of the Backdoor Roth IRA and Mega Backdoor Roth strategies:

The administration has proposed limitations on these strategies in the Fiscal Year 2024 Budget Proposal. However, these proposals have yet to be enacted.

There are two ways to transfer after-tax contributions into a Roth account, both of which are tax-free.

You can rollover your funds into a Roth IRA, which is a straightforward process.

Doing an in-plan conversion into your Roth solo 401k account is another option, and it's also tax-free.

Both transfers are possible because you contributed with after-tax dollars, which means the IRS doesn't require you to pay any taxes on conversions to a Roth account.

Here are the two methods in a concise list: