Starting a 401(k) on your own typically means opening a plan designed for self-employed individuals or business owners with no employees. Options like a solo 401(k) allow you to contribute both as the employer and the employee. This can lead to higher annual contribution limits than many other retirement accounts. Setting one up involves choosing a provider, completing a brief plan adoption process and deciding how you want to invest the funds. These plans offer tax-advantaged growth and can be used even if your business is a side gig.
A financial advisor can walk you through the benefits and drawbacks of different retirement accounts.
How a 401(k) Works
One popular option for self-directed retirement planning is a 401(k), a tax-advantaged retirement savings plan traditionally sponsored by an employer.
A 401(k) allows employees to save and invest a portion of their paycheck before taxes are taken out. These benefits include potential employer match contributions, tax deductions and the opportunity for tax-deferred compound growth.
Contributions to a traditional 401(k) are made pre-tax, reducing your taxable income for the year. Some employers even match a portion of your contributions, giving you a welcome boost to your retirement savings.
For example, if your employer matches 50% of your contributions up to 5% of your salary, and you earn $60,000 a year, that’s an additional $1,500 in your 401(k).
Predicting how much you can save in a 401(k) over time could be tricky. But a retirement calculator can help you estimate based on the size of your contributions and any employer matches.
What Is a Solo 401(k)?
A solo 401(k), also known as a one-participant 401(k) plan, works for self-employed individuals or business owners without employees, except for their spouse.
This plan provides all the advantages of a traditional 401(k) with one key distinction: higher contribution limits. By serving as both the employer and employee, you can contribute more to a solo 401(k). This allows you to boost your retirement savings at a faster pace.
This plan allows different types of investments such as mutual funds, stocks, bonds and even real estate.
Solo 401(k) Eligibility and Contribution Limits
A solo 401(k) is available to anyone who earns self-employment income, whether through freelance work, contract jobs or a small business. The key requirement is that the business has no full-time employees other than the owner and, if applicable, the owner’s spouse.
Part-time workers who do not meet federal long-term eligibility thresholds generally don’t disqualify the plan. As long as you have qualifying self-employment earnings and meet the no-employee rule, you can establish and contribute to a solo 401(k).
A solo 401(k) allows contributions in two roles: as the employee and as the employer. 1 As the employee, you can contribute up to the annual elective deferral limit, which is $24,500 for 2026, with an additional catch-up contribution if you’re 50 or older. 2 As the employer, you can add up to 25% of your net self-employment earnings. Combined employee and employer contributions cannot exceed the overall limit of $72,000 for 2026, or $80,000 if you qualify for catch-up contributions. 3
How to Setup a Solo 401(k)

Opening a solo 401(k) plan involves several steps to ensure that you meet IRS regulations. Here are five common steps you can take:
- Check your eligibility: Confirm that you qualify to open a solo 401(k) plan. Typically, you should be a self-employed individual or a small business owner with no full-time employees other than yourself and your spouse.
- Obtain an EIN: If you haven’t already, obtain an Employer Identification Number (EIN) from the IRS. This identifies your plan and report contributions and distributions. You must have an EIN to open a Solo 401(k) plan.
- Choose a provider: Research and select a financial institution or provider that offers solo 401(k) plans. This can be a bank, brokerage firm, or a specialized retirement plan provider.
- Select the type of plan: Decide whether you want a traditional solo 401(k) or a Roth solo 401(k). With a traditional plan, you will make pre-tax contributions, which could reduce your taxable income for the year. Roth 401(k) plan contributions, on the other hand, come from after-tax dollars that can provide tax-free withdrawals for your retirement.
- Review your plan agreement: Carefully read the plan agreement that you get from your provider. This document outlines the terms and features of your solo 401(k) plan. If it’s to your liking, complete and sign it.
Remember that solo 401(k) plans have specific rules and options that can vary between providers. So it’s important to review and understand the terms of your specific plan.
Calculate whether you have enough saved in your retirement accounts and if you’re on track to retire on time:
Retirement Calculator
Calculate whether or not you’re on track to meet your retirement savings goals.
About This Calculator
To estimate how much you may need to save for retirement, we begin by calculating how much you're expected to spend over the course of your retirement. This includes estimating the income you'll need based on your lifestyle preferences, then factoring in how many years you may spend in retirement. We assume a lifespan of 95 by default, though you can adjust it after your calculation is complete.
Once we have a clearer view of your total retirement needs, we use our models to evaluate your existing and future resources. This includes estimating retirement income from Social Security and the impact of current retirement plans, pensions and other accounts. For additional inputs and a comprehensive retirement plan, please see our full Retirement Calculator.
Assumptions
Lifespan: We assume you will live to 95. We stop the analysis there, regardless of your spouse's age.
Retirement accounts: We automatically distribute your future savings optimally among different retirement accounts. We assume that the IRS contribution limits for your retirement accounts increase with inflation.
Social Security: We estimate your Social Security income using your stated annual income and assuming you have worked and paid Social Security taxes for 35 years prior to retirement. Our estimate is sensitive to penalties for early retirement and credits for delaying claiming Social Security benefits.
Return on savings: We assume the percentage return on your savings differs by whether you're pre- or post-retirement and by account type, with a distinction between investment accounts and savings accounts. This assumption does not account for market volatility or investment losses and assumes positive growth over time. All investing involves risk, including the possible loss of principal.
SmartAsset.com is not intended to provide legal advice, tax advice, accounting advice or financial advice (Other than referring users to third party advisers registered or chartered as fiduciaries ("Adviser(s)") with a regulatory body in the United States). Articles, opinions, and tools are for general information only and are not intended to provide specific advice or recommendations for any individual. The retirement calculator is meant to demonstrate different potential scenarios to consider, and is not intended to provide definitive answers to anyone's financial situation. We always suggest that you consult your accountant, tax, legal or financial advisor concerning your individual situation.
This is not an offer to buy or sell any security or interest. All investing involves risk, including loss of principal. Working with an adviser may come with potential downsides such as payment of fees (which will reduce returns). Past performance is not a guarantee of future results. There are no guarantees that working with an adviser will yield positive returns. The existence of a fiduciary duty does not prevent the rise of potential conflicts of interest.
Solo 401(k) Tax Advantages
A solo 401(k) offers flexibility in how the IRS taxes contributions and withdrawals. With a traditional Solo 401(k), you contribute pre-tax dollars. This lowers your taxable income in the year you contribute. This can reduce your current tax bill while allowing your investments to grow tax-deferred until retirement. The IRS taxes withdrawals in retirement as ordinary income.
Alternatively, a Roth solo 401(k) allows contributions with after-tax dollars. While you don’t get a deduction in the year you contribute, your money grows tax-free, and qualified withdrawals in retirement are also tax-free. This can be advantageous if you expect to be in a higher tax bracket in the future.
Another benefit is the ability to split contributions between the traditional and Roth portions of the plan. This approach can diversify your tax exposure in retirement, giving you more flexibility in managing your taxable income later in life.
Choosing between traditional and Roth solo 401(k) contributions depends on your current income, tax bracket, and long-term financial goals. Some self-employed individuals use both to balance tax savings now with tax-free income in the future.
Alternatives to a Solo 401(k)
While a solo 401(k) can be a good fit if you are self-employed, it’s not the only option. Other retirement savings alternatives include traditional and Roth IRAs, SEP IRAs and SIMPLE IRAs.
When compared with IRAs, a Solo 401(k) allows higher contribution limits. And unlike SEP IRAs, a solo 401(k) permits Roth contributions, which can offer you tax-free withdrawals in retirement.
Common Mistakes to Avoid With a Solo 401(k)
A solo 401(k) comes with real responsibility. Without an employer or HR department overseeing the plan, mistakes fall entirely on you, and some of them carry serious financial or legal consequences. Being aware of the most common errors can help you protect your plan and make the most of its benefits.
One of the most frequent mistakes is missing the plan establishment deadline. The plan must be established by December 31st of the tax year in which you want to begin participating. If you wait until January to set up your plan hoping to count contributions toward the prior year, you’ll be out of luck.
Miscalculating your allowable contributions is another common error. Many self-employed individuals mistakenly base their employer contribution on gross self-employment income rather than net earnings after the self-employment tax deduction. Overcontributing, even accidentally, can trigger IRS penalties so it’s worth double-checking your math or consulting a tax professional before making contributions. If your business grows and you bring on a full-time employee, your solo 401(k) eligibility may evaporate quickly.
Many solo 401(k) holders are also unaware of the Form 5500-EZ filing requirement. Once your plan’s total assets exceed $250,000 at the end of a plan year, you are required to file this form annually with the IRS. 4 Missing the deadline can result in steep penalties that accumulate quickly, so mark it on your calendar well in advance.
Finally, treat your solo 401(k) as the long-term retirement vehicle it’s designed to be. Withdrawing funds before age 59½ typically triggers a 10% early withdrawal penalty on top of ordinary income taxes, which can significantly erode your savings. If you anticipate needing liquidity, explore whether your plan allows for loans before resorting to an early withdrawal.
Bottom Line

Regardless of whether you choose a solo 401(k) or another retirement savings option, it’s essential to start saving as early and consistently as possible. The optimal retirement plan will depend on your individual circumstances, including your income, tax situation and financial goals.
Tips for Retirement Planning
- Retirement planning takes a lot of strategizing and an understanding of a variety of investments. This is something that financial advisors can help you with. Finding a financial advisor doesn’t have to be hard. SmartAsset’s free tool matches you with vetted financial advisors who serve your area, and you can have a free introductory call with your advisor matches to decide which one you feel is right for you. If you’re ready to find an advisor who can help you achieve your financial goals, get started now.
- You may want to make sure you’re saving enough money for retirement. SmartAsset’s free retirement calculator can help you estimate whether you’re on track for what you need to retire on time.
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Article Sources
All articles are reviewed and updated by SmartAsset’s fact-checkers for accuracy. Visit our Editorial Policy for more details on our overall journalistic standards.
- “One Participant 401k Plans | Internal Revenue Service.” Home, https://www.irs.gov/retirement-plans/one-participant-401k-plans. Accessed Apr. 25, 2026.
- “401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 | Internal Revenue Service.” Home, https://www.irs.gov/newsroom/401k-limit-increases-to-24500-for-2026-ira-limit-increases-to-7500. Accessed Apr. 25, 2026.
- “Publication 560 (2025), Retirement Plans for Small Business | Internal Revenue Service.” Home, https://www.irs.gov/publications/p560. Accessed Apr. 25, 2026.
- “One Participant 401k Plans | Internal Revenue Service.” Home, https://www.irs.gov/retirement-plans/one-participant-401k-plans. Accessed Apr. 25, 2026.
