If you're one of millions of Americans without access to a 401(k) or other retirement plan through a job, you may still have options to save for retirement when you hang your own shingle. Meet the solo 401(k)—also known as the self-employed 401(k), individual 401(k), personal 401(k), or, to use the IRS's preferred term, the one-participant 401(k).
Whatever you call it, the solo 401(k) is known for its high contribution limits that let people with no employees, except a spouse who earns income from the business, save a lot for retirement. That includes freelancers and gig workers to sole proprietors, LLCs (limited liability companies), S corporations, C corporations, business owners, and partnerships with no employees.
Solo 401(k) contribution limits for 2025
In 2025, aggregate contributions can reach up to $70,000 if you're under 50. You can contribute an additional $7,500 in catch-up contributions if you're age 50-59 or age 64 or older. Those between age 60 and 63 can contribute an additional $11,250 in catch-up contributions if the plan allows.
While those are the absolute maximums that can be contributed to a solo 401(k), the amount you can contribute may be different. That's because solo 401(k)s come with a little nuance. With a solo 401(k), you can make contributions in 2 ways: as the employee and as the employer. Each portion of that equation has a different limit.
In 2025, you can contribute up to $23,500 pre-tax or Roth dollars to your solo 401(k) as an employee. If you're age 50-59 or older than 64, you can add a catch-up contribution of $7,500, for a total employee contribution of $31,000. If you're age 60-63 and your plan allows it, you can add a catch-up contribution of $11,250, for a total employee contribution of $34,750.1
You're also allowed to contribute up to 25% of compensation (after Social Security and Medicare taxes) as the employer profit-sharing contribution.2 The IRS limits the amount of compensation that determines retirement contributions; for 2025, the limit is $350,000. As an example, a consultant under 50 with earned income of $100,000 can contribute $23,500 as an employee and up to $18,587 as the employer for a total of $42,087.3 You can contribute up to the limits described for employer plus employee, or 100% of your compensation, whichever is less.
Keep in mind that if you have access to a 401(k) plan, your employee contribution limit applies across all plans, not per plan. So if you max out your contributions to a different employer-sponsored 401(k), you may only be able to make employer contributions to your solo 401(k).
The deadline for self-employed individuals and owner-only businesses to make both the employee salary deferral and company profit sharing contribution is the business's tax filing deadline, including extensions. Contribution deadlines may be different in the year the plan is established. For the year salary deferrals are to commence, generally participants (including self-employed individuals and spouses of owners if they are also participating employees) must make a written salary deferral election by the business's year end.
If your business isn't incorporated, you can generally deduct contributions for yourself from your personal income. If your business is incorporated, you can count these contributions as a business expense. Consult with a tax professional for your situation.
Solo 401(k) contribution limits for 2026
In 2026, aggregate contributions can reach up to $72,000 if you're under 50. You can contribute an additional $8,000 in catch-up contributions if you're age 50-59 or age 64 or older. Those between age 60 and 63 can contribute an additional $11,250 in catch-up contributions if the plan allows.
While those are the absolute maximums that can be contributed to a solo 401(k), the amount you can contribute may be different. That's because solo 401(k)s come with a little nuance. With a solo 401(k), you can make contributions in 2 ways: as the employee and as the employer. Each portion of that equation has a different limit.
In 2026, you can contribute up to $24,500 pre-tax or Roth dollars to your solo 401(k) as an employee. If you're age 50-59 or older than 64, you can add a catch-up contribution of $8,000, for a total employee contribution of $32,500. If you're age 60-63 and your plan allows it, you can add a catch-up contribution of $11,250, for a total employee contribution of $35,750.1
You're also allowed to contribute up to 25% of compensation (after Social Security and Medicare taxes) as the employer profit-sharing contribution.2 The IRS limits the amount of compensation that determines retirement contributions; for 2026, the limit is $360,000.
Keep in mind that if you have access to a 401(k) plan, your employee contribution limit applies across all plans, not per plan. So if you max out your contributions to a different employer-sponsored 401(k), you may only be able to make employer contributions to your solo 401(k).
The deadline for self-employed individuals and owner-only businesses to make both the employee salary deferral and company profit sharing contribution is the business's tax filing deadline, including extensions. Contribution deadlines may be different in the year the plan is established. For the year salary deferrals are to commence, generally participants (including self-employed individuals and spouses of owners if they are also participating employees) must make a written salary deferral election by the business's year end.
If your business isn't incorporated, you can generally deduct contributions for yourself from your personal income. If your business is incorporated, you can count these contributions as a business expense. Consult with a tax professional for your situation.
Solo Roth 401(k) contribution limits
If your solo 401(k) plan allows Roth contributions, the Roth solo 401(k) contribution limit is the same as the pre-tax contribution limit. If you contribute both Roth and pre-tax deferrals to your plan, your combined contributions can't exceed the annual limit. When the time comes to withdraw, the Roth withdrawals are tax-free as long as you're at least 59½, disabled, or taking a distribution from an inherited account, and the 5-year aging requirement has been met.4 SECURE 2.0 allows employers to make matching and profit-sharing contributions to Roth accounts, although this is not available to all plans.5 Beginning in 2026, participants in 401(k)s who are 50 or older and had prior-year W-2 compensation of $145,000 or greater must make any catch-up contributions on a Roth basis. The compensation figure rises to $150,000 for the 2026 tax year.
What if I contributed too much to a solo 401(k)?
If you contributed too much to a solo 401(k), remove what the IRS calls "excess deferral." Excess deferrals must usually be removed by April 15 of the year following the year in which the deferral occurred. If you do so by Tax Day of the following year, usually April 15, you'll likely just have to pay any applicable taxes on the earnings from what you overcontributed.
If you do so after that deadline, the amount of the withdrawal could be double taxed: once in the year you put in the money and then again the year the money is taken out to correct the error. You may also have to pay a 10% early withdrawal tax.
How to open a solo 401(k)
You can open a solo 401(k) at a number of providers, including Fidelity. Factors you might consider are plan offerings such as traditional, Roth, and after-tax contributions; investment options; fees; administrative support; the ability to take out loans; the plan's ability to accept rollovers; and electronic deposit capabilities. Once you open a solo 401(k) you or whoever you name as plan administrator, if not yourself, are responsible for making contributions and complying with the terms of the plan.
Anything else I should know about a solo 401(k)?
If your solo 401(k) plan's balance is above $250,000 at the end of the plan year, you'll likely have to file tax form 5500-EZ for one-participant plans. If you've terminated your plan, you'll need to file a final return indicating that all assets have been distributed. Also, solo 401(k)s typically don't provide unlimited creditor protection under ERISA (Employee Retirement Income Security Act of 1974).