Can you max out two 401(k)s with a side business?

Two plans, but not two limits

If you have a 401(k) at work and also run a side business, that business can open the door to a second 401(k). It is natural to assume that two plans means two full limits. That is only half right.

A 401(k) has two kinds of money going in: what you contribute as an employee, and what the employer contributes. The two follow different rules.

The employee limit follows you, not the plan

The part you contribute as an employee has one limit per person, across every plan you have. For 2026, that limit is $24,500.

So if you already max out your plan at work, you cannot add more as an employee anywhere else, including your side business’s 401(k). Splitting it between the two plans is fine, but the total still counts against the same $24,500.

Where the side business adds room

Your side business can also pay into its own 401(k) as the employer. That employer contribution has a separate limit from your work plan, so it can go in on top of what you already put in at work.

For a self-employed owner, the employer contribution can be a little under 20% of the business’s profit. Take a hypothetical side business with $50,000 of profit: it could add more than $9,000 for you as the employer, even if you already maxed out your employee contribution at work.

So you cannot max out the employee part twice, but your side business can add its own contribution on top. How much makes sense depends on your profit, your cash flow, and the rest of your tax return.

How we handle it

At Sansone CPA & Financial, we coordinate your tax, investment, and retirement decisions so side-business profit and retirement contributions are planned together, not one at a time. That is the core of our tax and financial planning for business owners in Crystal Lake, IL.