Can You Have Both a Solo 401k and a Regular 401k? Rules & Contribution Limits

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A common question about Solo 401k eligibility is: Can I contribute to a Solo 401k if I also have a 401k plan at my day job? 

The short answer — yes, you can! As long as you meet the Solo 401k eligibility requirements, you’re allowed to contribute to both plans. 

However, there’s a catch. Employee contribution amounts across both plans are aggregated, meaning you need to track your total contributions carefully to avoid exceeding the IRS limits. Simply put, as an employee the maximum you can contribute in 2025 is $23,500, no matter if it’s to your regular or Solo 401k. In this guide, we’ll discuss how this works and what you need to keep in mind.

How to Contribute to Both Accounts

If you have both a Solo 401k and a 401k at work, you’ll need to do some extra calculations to make sure you don’t overcontribute, especially when it comes to employee contributions.

How Employee Contributions Work For Both Plans

With a regular 401k, you contribute as an employee and your employer may offer matching contributions. As an employee, your contribution limit of a regular 401k is: 

📝 Disclosure: IRS limits and rules change annually. Be sure to check the latest guidance before determining your contribution amounts. 

With a Solo 401k, you can contribute as both an employer and an employee. The employee contribution limits are the same as a regular 401k. Employee contribution limits are per person, not per plan. 

✏️ Example: In 2025, if you contribute $10,000 to your company 401k, the maximum you can contribute is $13,500 as an employee to your Solo 401k. The total cannot exceed the annual employee limit set by the IRS.

Employer Contributions Are Separate

Unlike employee contributions, employer contributions do not get combined. That means if you have a Solo 401k, you can still make employer contributions, even if you max out your employee contributions elsewhere.

You cannot make employer contributions to a regular 401k (since you’re not the employer), but with a Solo 401k, you control how much you contribute as the employer.

✏️ Example: If you max out your employee contributions in your work 401k, you can’t contribute any more as an employee to your Solo 401k. But you can still contribute as an employer.

Catch-Up Contributions for Solo 401k and Regular 401k

If you’re 50 or older, you can make catch-up contributions but only after maxing out your employee contributions.

Since employee limits apply to both accounts, you can choose which plan receives your catch-up contributions.

✏️ Example: If your work 401k doesn’t allow catch-up contributions, you can allocate them to your Solo 401k instead.

Solo 401k vs. Regular 401k — Investment Options & Roth Accounts

Some Solo 401k plans come with a Roth option and let you invest in almost any asset class like stocks, ETFs, real estate, and even crypto. 

A regular 401k on the other hand, is often managed by your employer, has fewer investment choices, and is usually limited to ETFs or mutual funds. Some workplace plans may not offer a Roth option at all.

Since employee contributions are combined across both plans, deciding where to allocate your funds depends on two key questions.

Are You Considering Contributing to a Roth Account?

Your Solo 401k may have a Roth option, but your regular 401k might only offer a pre-tax account. Only employee contributions can be put into a Roth account, so if you max out your regular 401k, you won’t have any room left to contribute as an employee to your Solo 401k.

If you prefer Roth contributions in order to get tax-free withdrawals in retirement, prioritizing your Solo 401k employee contributions could make more sense.

Does Your Employer Offer 401k Matching?

Let’s say you want to max out your Roth contributions for the year, but your regular 401k does not offer a Roth option. In that case, it makes sense to max out your employee contributions to your Solo 401k instead.

However, if your employer offers a match, it may be best to contribute enough money to your regular 401k to receive the full employer match before focusing on your Solo 401k.

📝 Disclosure: Carry does not provide Tax advice, consult with a professional to understand your specific situation to determine the best course of action.

What is the Maximum I Can Contribute to Both Plans?

If you have both a 401k at work and a Solo 401k, you can potentially contribute double the standard limit as long as you follow the IRS rules.

✏️ Example: If you’re under 50 in 2025, you could contribute up to $70,000 to each plan — a total of $140,000 if you meet all requirements.

Maxing Out Your Regular 401k

To max out your regular 401k, you must:

❌ In reality, most employers don’t contribute much to Solo 401k matches. The average employer match is only around 5% of salary.

Maxing Out Your Solo 401k

Once you hit your employee contribution limit, you can still maximize employer contributions in your Solo 401k. However, your business must generate enough income.

✏️ Example:

Then, contribute $70,000 as an employer to your Solo 401k assuming your business generates enough net income. Your total contributions for the year would be $93,500 — significantly higher than just relying on one plan.

Final Thoughts

If you’re self-employed and also have a 401k at work, you can take advantage of both plans. However, you need to track your employee contributions carefully to stay within IRS limits.

✅ Max out employer contributions in your Solo 401k

✅ Consider Roth contributions if your work 401k doesn’t offer them

✅ Take full advantage of employer matching before contributing elsewhere

By understanding how both plans work together, you can maximize your retirement savings while staying compliant with IRS rules.