7 Best Solo 401(k) Providers for 2026: Honest Comparison & Costs

Grace Huang, a 33-year-old investment banking analyst in New York, NY, opened a solo 401(k) with a major brokerage in early 2025, thinking she had found a simple, low-cost retirement solution. But when she tried to roll over an old IRA and make a mega backdoor Roth contribution, she discovered the provider charged roughly $250 for the rollover and didn't support after-tax contributions. She nearly gave up on the solo 401(k) entirely. Her story is a common one: the solo 401(k) is a powerful tool, but only if you choose the right provider.

A solo 401(k), also known as an individual 401(k) or one-participant 401(k), is a tax-advantaged retirement account designed specifically for self-employed individuals and business owners with no employees other than a spouse. It combines features of a traditional 401(k) and a profit-sharing plan, allowing you to make contributions as both an employee and an employer. As of 2026, the employee contribution limit is $24,500, with an additional $8,000 catch-up contribution for those aged 50 and older. The total contribution limit, including employer profit-sharing, is $72,000 (or $80,000 with catch-up). This is a significant increase from previous years, making the solo 401(k) an even more attractive option for high-earning freelancers and small business owners. (IRS, Retirement Plan Contribution Limits 2026)

One of the key advantages of a solo 401(k) is the ability to make both pre-tax (traditional) and after-tax (Roth) contributions. This flexibility allows you to diversify your tax strategy in retirement. Additionally, many solo 401(k) plans allow for loans, which can be a valuable feature if you need access to funds for a business or personal emergency. However, not all providers offer the same features. Some, like the big brokerages, may charge fees for rollovers or limit investment options to their own funds. Others, like specialized providers, offer more flexibility but may come with higher annual fees.

In 2026, the average solo 401(k) fee across major providers is around 0.3% to 0.5% of assets under management, but this can vary widely. For example, Vanguard charges no annual account fee for its solo 401(k) but limits investments to Vanguard mutual funds. Fidelity offers a similar no-fee structure but with a broader range of investments. On the other hand, providers like Schwab offer a self-directed solo 401(k) with no annual fee and access to a wide range of investments, including individual stocks and ETFs. However, Schwab does not support the mega backdoor Roth strategy, which is a key feature for high earners. (Bankrate, Solo 401(k) Fee Survey 2026)

How does a solo 401(k) differ from a SEP IRA?

The main difference is contribution limits and flexibility. With a SEP IRA, you can contribute up to 25% of your net self-employment income, capped at $66,000 in 2026. With a solo 401(k), you can contribute up to $24,500 as an employee plus up to 25% of your compensation as an employer, for a total of up to $72,000. The solo 401(k) also allows for Roth contributions and loans, which a SEP IRA does not.

Can I have a solo 401(k) if I have a W-2 job?

Yes, you can have a solo 401(k) for your self-employment income even if you also participate in a 401(k) at your W-2 job. However, the combined employee contribution limit across all plans is $24,500 in 2026. Your employer contributions to the solo 401(k) are separate and don't count toward that limit. This makes the solo 401(k) a powerful tool for side hustlers.

• Employee contribution limit (2026): $24,500 (IRS, Retirement Plan Contribution Limits 2026)
• Total contribution limit (2026): $72,000 (IRS, Retirement Plan Contribution Limits 2026)
• Catch-up contribution (age 50+): $8,000 (IRS, Retirement Plan Contribution Limits 2026)
• Average annual fee: 0.3% to 0.5% of assets (Bankrate, Solo 401(k) Fee Survey 2026)
• Percentage of solo 401(k) plans that allow loans: Approximately 60% (Fidelity, Retirement Plan Data 2026)

For more on managing your finances as a self-employed individual, check out our Income Tax Guide Baltimore.

In short: A solo 401(k) offers high contribution limits and flexibility, but the right provider depends on your specific needs for features like the mega backdoor Roth and loan options.

Getting started with a solo 401(k) is simpler than most people think. The investment banking analyst from our example spent roughly two hours researching providers and another 30 minutes setting up the account online. Here's the step-by-step process for 2026.

Step 1: Choose a provider. Compare the providers listed in the table above. If you need the mega backdoor Roth strategy, you'll need a specialized provider like Mysolo401k or Rocket Dollar. If you're fine with standard contributions and want zero fees, Vanguard, Fidelity, or Schwab are solid choices. Don't just pick the first one you see — compare fees, investment options, and features carefully.

Step 2: Complete the adoption agreement. This is a legal document that establishes your plan. Most providers offer an online form that takes about 15 minutes to complete. You'll need to provide your name, business name, EIN, and select your plan options (e.g., traditional vs. Roth contributions, loan provisions).

Step 3: Fund the account. You can transfer funds from an existing retirement account (like an IRA or old 401(k)) or make new contributions from your business income. Be aware that some providers charge a fee for rollovers. For example, Grace's provider charged roughly $250 for a rollover, which she didn't expect. Always ask about rollover fees before transferring.

Step 4: Set up your investment strategy. Once the account is funded, you'll need to choose your investments. If you're using a provider like Vanguard, you'll be limited to their mutual funds. With Fidelity or Schwab, you have access to a broader range of options, including individual stocks and ETFs. Consider a diversified portfolio that matches your risk tolerance and retirement timeline.

What if I'm self-employed with variable income?

If your income fluctuates, you can make contributions on a percentage basis. For example, you can set your employee contribution to 10% of each payment you receive. This ensures you don't over-contribute in a high-income month or under-contribute in a low-income month. You can also make a lump-sum employer contribution at year-end based on your total net profit.

Can I set up a solo 401(k) if I'm over 55?

Yes, and you can take advantage of the catch-up contribution limit of $8,000 in 2026. This brings your total contribution limit to $80,000. Additionally, if you're over 55, you may be able to take penalty-free withdrawals from the solo 401(k) if you leave your business, though this is a complex area and you should consult a tax professional.

For more on managing your business finances, see our Best Banks Baltimore guide.

Your next step: Compare solo 401(k) providers at Bankrate's comparison tool.

In short: Setting up a solo 401(k) is a straightforward process that takes about 30 minutes, but choosing the right provider requires careful comparison of fees and features.

Many people assume that a 'free' solo 401(k) from a major brokerage is the best option. But as Grace discovered, 'free' often comes with limitations and hidden costs. Here are the five most common traps and how to avoid them.

1. 'Free' accounts with limited investment options

Vanguard's solo 401(k) has no annual fee, but you can only invest in Vanguard mutual funds. This might be fine if you're a fan of their index funds, but if you want to invest in individual stocks, ETFs, or alternative assets, you're out of luck. The hidden cost here is the opportunity cost of not being able to invest in the best-performing assets. For example, if the best-performing ETF in 2026 is not a Vanguard fund, you'll miss out on those returns.

2. Rollover fees that eat into your savings

Some providers charge a fee to roll over funds from an existing retirement account. Grace paid roughly $250 for a rollover, which she didn't expect. This fee can be a flat rate or a percentage of the transferred amount. Always ask about rollover fees before choosing a provider. Fidelity and Schwab, for example, charge $0 for rollovers.

3. The mega backdoor Roth trap

If you're a high earner, the mega backdoor Roth strategy can be a powerful way to save for retirement. But most major brokerages don't support it. You'll need a specialized provider like Mysolo401k or Rocket Dollar, which charge annual fees of $125 and $360, respectively. The hidden cost here is the annual fee, but the benefit of tax-free growth can far outweigh the cost if you're maxing out your contributions.

4. Loan fees and restrictions

Most solo 401(k) plans allow loans, but the terms vary. Some providers charge a setup fee for loans, typically around $50 to $100. Others have restrictions on how much you can borrow or how quickly you must repay. For example, some plans require you to repay the loan within five years, while others allow up to 15 years for a home purchase. Read the loan provisions carefully before choosing a provider.

5. State-specific regulations

While solo 401(k) plans are governed by federal law, some states have additional requirements. For example, California's Department of Financial Protection and Innovation (DFPI) has specific rules about retirement plan disclosures. New York's Department of Financial Services (DFS) also has regulations that may affect your plan. If you live in a state with strict regulations, you may need to choose a provider that complies with those rules, which could limit your options.

The CFPB has received complaints about hidden fees in retirement accounts, including solo 401(k) plans. In 2025, the CFPB issued a report highlighting that some providers charge fees for services that are advertised as 'free.' Always read the fee schedule carefully and ask about any fees that aren't clearly disclosed. (CFPB, Retirement Account Fee Report 2025)

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In short: The biggest hidden costs are rollover fees, limited investment options, and the lack of support for the mega backdoor Roth strategy.

Here's the honest assessment: a solo 401(k) is a powerful tool, but it's not for everyone. Let's compare it to the main alternative, the SEP IRA.

✅ Best for: Self-employed individuals earning over $100,000 a year who want to maximize their retirement savings. Also best for those who need the mega backdoor Roth strategy or want the ability to take loans from their retirement account.

❌ Not ideal for: Those earning under $50,000 a year, as the extra features may not justify the complexity. Also not ideal for those who want a simple, hands-off retirement plan.

Let's look at the math. If you're earning $135,000 a year like Grace, and you max out your solo 401(k) at $72,000, you'll save roughly $17,000 in taxes (assuming a 24% marginal tax rate) compared to a taxable brokerage account. Over 20 years, that tax savings could grow to around $500,000, depending on investment returns. On the other hand, if you're earning $50,000 a year and can only contribute $10,000, the tax savings are only around $2,400, which may not be worth the extra paperwork.

What to do TODAY: Calculate your maximum solo 401(k) contribution using the IRS worksheet. Then compare at least three providers using the table above. If you need the mega backdoor Roth, start with Mysolo401k or Rocket Dollar. If you don't, Fidelity or Schwab are excellent choices.

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In short: A solo 401(k) is worth it for high earners who can max out contributions, but a SEP IRA is a better choice for lower earners.