How a Self-Employed Person Can Build a Retirement Plan From Scratch

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A self employed retirement plan is any tax-advantaged account structured for workers without access to an employer-sponsored 401(k). According to IRS guidance on self-employment retirement plans, sole proprietors, freelancers, and independent contractors each qualify for multiple plan types with contribution limits far exceeding a standard IRA. The right plan can reduce taxable income substantially while building long-term wealth.

With more than 16 million self-employed Americans operating without workplace retirement benefits, the stakes for getting this decision right have never been higher.

Which Retirement Plan Types Are Available to the Self-Employed?

Self-employed workers have three primary retirement plan options: the SEP-IRA, the Solo 401(k), and the SIMPLE IRA. Each carries distinct contribution limits, setup requirements, and tax treatments.

The SEP-IRA is the simplest to open. It allows contributions of up to 25% of net self-employment income, capped at $69,000 in 2024 and $70,000 in 2025, according to IRS SEP-IRA rules. There is no Roth option, and the account accepts only employer contributions, meaning no employee-side catch-up contributions are available.

The Solo 401(k) is the most powerful option for high earners. It lets you contribute both as an employee (up to $23,500 in 2025) and as an employer (up to 25% of compensation), with a combined ceiling of $70,000. If you are age 50 or older, an additional $7,500 catch-up contribution is permitted. Many brokerages now offer Roth Solo 401(k) options, adding post-tax flexibility. You can compare current 401(k) contribution limits for 2026 to plan ahead.

The SIMPLE IRA suits self-employed individuals with one to a few employees. Employee contributions are limited to $16,500 in 2025, with a required employer match. It is easier to administer than a Solo 401(k) but less generous at higher income levels.

How Do You Calculate Your Allowable Contributions?

Calculating contributions for a self employed retirement plan requires adjusting your net earnings first. You cannot simply use gross revenue. The IRS requires you to subtract the deductible portion of self-employment tax (half of the 15.3% SE tax) from net self-employment income before applying the contribution percentage.

For a SEP-IRA, the effective contribution rate works out to roughly 18.59% of net self-employment income after the SE tax deduction, not 25%. This is a common miscalculation that leads to excess contributions and IRS penalties. IRS Publication 560 includes worksheets that walk through the exact calculation step by step.

Example Calculation for a Solo 401(k)

Assume your net self-employment income is $120,000. After subtracting the SE tax deduction, your adjusted net earnings are approximately $111,000. You can contribute up to $23,500 as an employee, plus 25% of $111,000 ($27,750) as the employer, for a total of $51,250 in 2025. That is well below the $70,000 cap, so the full amount is deductible.

Excess contributions trigger a 6% excise tax per year they remain in the account, compounding the penalty over time. Use IRS-provided worksheets or a CPA to verify your numbers annually.

Why Income Fluctuations Complicate the Math

Freelance income rarely arrives in a straight line. A consultant who earns $180,000 one year and $90,000 the next faces a dramatically different contribution ceiling each year, and running last year’s numbers in the current year is one of the most reliable ways to trigger an excess contribution error.

The practical solution is to calculate contributions conservatively mid-year using a projected income estimate, then finalize the number after December 31 once actual net earnings are confirmed. This is especially important for Solo 401(k) holders because the employee contribution side (up to $23,500) is not income-dependent the way the employer side is. You can contribute the full employee amount even in a lighter income year, as long as you have at least that much in net self-employment earnings.

One more detail worth knowing: the Solo 401(k) employee contribution is based on W-2 wages if your business is structured as an S-corp, not on net self-employment income. The calculation method differs, and the distinction matters when you run the numbers. A CPA familiar with self-employment structures can catch these nuances before they become tax problems.

Traditional vs. Roth: Which Tax Structure Fits Self-Employment?

The core tax decision for a self employed retirement plan is whether to defer taxes now (traditional/pre-tax) or pay taxes now and withdraw tax-free later (Roth). Self-employed income tends to fluctuate, which makes this decision especially strategic compared to a salaried employee whose bracket is predictable year to year.

In high-income years, traditional pre-tax contributions reduce your adjusted gross income immediately. A sole proprietor in the 32% federal bracket who contributes $30,000 to a Solo 401(k) saves roughly $9,600 in federal taxes that year. This is a meaningful, real-time cash flow benefit for irregular earners.

In lower-income years, when starting a business or during slow periods, Roth contributions make more sense. You pay taxes at today’s lower rate, and all future growth comes out tax-free. For a deeper comparison of these two paths, see our guide on Roth IRA vs. Traditional IRA in 2026.

Using Both: The Mega Backdoor Strategy

Some Solo 401(k) plans allow after-tax contributions beyond the Roth and pre-tax limits, up to the $70,000 total cap. These can then be converted to Roth inside the plan, a strategy known as the mega backdoor Roth. Not all plan documents permit this, so verify with your brokerage before attempting it.

The mechanics matter here. The after-tax contribution itself is not a deduction, but once converted to Roth inside the plan, all future growth is tax-free. For a high earner who has already maxed the pre-tax and Roth employee contributions, this is one of the few remaining ways to get additional money into a tax-sheltered account beyond standard limits.

Splitting Contributions Between Tax Treatments

Nothing requires you to commit entirely to one approach. A freelancer who expects high income this year but anticipates a lower-income transition period in the next two or three years might direct the full $23,500 employee contribution to Roth now, then shift to pre-tax contributions when income rises again. The Solo 401(k)’s flexibility to toggle between tax treatments year to year is a genuine structural advantage over both the SEP-IRA and the SIMPLE IRA, neither of which offers a Roth option at all.

According to IRS self-employment retirement guidance, the tax treatment election applies at the time of contribution and cannot be retroactively changed. Making the call deliberately, rather than defaulting to one approach, is where real tax planning value accumulates over time.

How Do You Actually Open and Fund a Self-Employed Retirement Account?

Opening a self employed retirement plan is straightforward at most major brokerages. The process takes one to three business days online, and most platforms charge no account fees.

For a Solo 401(k), the plan document must be established by December 31 of the tax year in which you want to make contributions. Contributions themselves can be funded up to the tax filing deadline, including extensions (October 15 for most sole proprietors). A SEP-IRA has more flexibility: the account can be opened and fully funded up to the filing deadline, including extensions.

Where to Open Each Account Type

Fidelity, Charles Schwab, and Vanguard all offer no-fee Solo 401(k) and SEP-IRA accounts. Fidelity and Schwab currently support Roth Solo 401(k) contributions; Vanguard does not as of mid-2025. For plan document complexity or employee-matching needs, working with a third-party administrator (TPA) provides more customization. Once your account is open, consider diversifying into low-cost index funds. Our guide to best index funds for beginners is a practical starting point.

Funding consistency matters more than timing. A freelancer who contributes $1,000 per month to a Solo 401(k) earning a 7% average annual return accumulates roughly $567,000 over 20 years, according to standard compound growth calculations. Automating transfers quarterly, aligned with estimated tax payments, reduces the risk of spending the money before investing it.

How to Structure Contributions Around Irregular Income

Most financial advice assumes a predictable paycheck. Self-employed income does not cooperate with that assumption. A practical approach is to treat retirement contributions as a percentage of each deposit rather than a fixed monthly amount. When a $15,000 contract payment arrives, transferring 15% to 20% directly into the retirement account before paying other expenses removes the temptation to spend it first.

Quarterly is the right cadence for most freelancers, because it aligns with estimated federal tax payment due dates (April 15, June 15, September 15, and January 15). Running both calculations at the same time, estimated tax owed and retirement contribution available, forces a realistic accounting of cash flow. Keeping a separate savings buffer of two to three months of expenses outside the retirement account prevents the common mistake of needing to withdraw retirement funds during a slow business period, which triggers taxes and penalties on top of the income shortfall.

How Do You Stay Compliant and Avoid IRS Penalties?

Self-employed retirement plans carry specific IRS reporting requirements that result in significant penalties when ignored. Understanding the rules upfront prevents costly surprises at tax time.

Solo 401(k) plans with assets exceeding $250,000 at year-end must file Form 5500-EZ with the IRS. Failure to file carries a penalty of $250 per day, up to $150,000. SEP-IRAs and SIMPLE IRAs have no annual filing requirement, which makes them lower-maintenance for compliance-averse freelancers.

Excess contributions are the second most common mistake. Contributing more than the IRS limit, even by a small amount, triggers a 6% excise tax annually until the excess is withdrawn. Tracking income fluctuations carefully and running contribution calculations before the year-end deadline prevents this. If you are also managing variable cash flow, pairing your retirement strategy with a well-structured budget helps. Our guide on how to create a monthly budget that works covers the mechanics in detail.

Self-employed individuals must also continue paying self-employment tax (15.3% on the first $176,100 of net earnings in 2025) regardless of retirement contributions. Retirement contributions reduce income tax, not SE tax, so quarterly estimated tax payments remain mandatory throughout the year.

The Form 5500-EZ Filing Threshold and What to Do About It

The $250,000 filing threshold catches many Solo 401(k) holders off guard because the account balance crosses it gradually. A freelancer who has been contributing for ten years at a moderate rate may not notice when assets push past the threshold. The penalty structure is severe enough that missing even one filing can generate a five-figure bill.

The solution is simple: set a calendar reminder each January to check the prior year-end balance. If it exceeds $250,000, Form 5500-EZ is due by July 31 of the following year. The form itself is not complicated, but the deadline is firm. Several tax software platforms and CPAs who specialize in self-employment taxes offer Form 5500-EZ preparation as a standalone service at modest cost, typically far less than one day of penalty exposure.

Required Minimum Distributions for Self-Employed Retirement Accounts

Required minimum distributions (RMDs) apply to Solo 401(k)s and SEP-IRAs beginning at age 73, the same threshold that applies to traditional IRAs under current IRS rules. The calculation uses the account balance as of December 31 of the prior year divided by a life expectancy factor from the IRS Uniform Lifetime Table.

One advantage the Solo 401(k) holds over the SEP-IRA: if you are still working and generating self-employment income past age 73, you may be able to delay RMDs from your Solo 401(k) until you retire, depending on how the plan document is written. A SEP-IRA does not offer this option. For those who expect to continue freelancing into their seventies, this distinction is worth factoring into the initial plan selection decision rather than trying to correct it later.

When Should You Switch Plans or Combine Strategies?

The right plan at $60,000 in annual self-employment income is rarely the right plan at $200,000. Knowing when your current structure is no longer serving you well is part of managing a self-employed retirement strategy over time.

The clearest trigger for switching is income growth. A freelancer who started with a SEP-IRA for simplicity and is now earning above $100,000 consistently should run a comparison against Solo 401(k) contribution limits. At $120,000 in net self-employment income, a SEP-IRA allows roughly $22,300 in contributions (applying the 18.59% effective rate). A Solo 401(k) at the same income level, as shown in the earlier calculation example, allows $51,250. That $28,950 gap translates directly to a larger tax deduction and faster account accumulation.

Hiring employees is the other major inflection point. A Solo 401(k) is only available to business owners with no full-time employees other than a spouse. The moment you bring on a qualifying employee, the plan must convert to a standard 401(k) with nondiscrimination testing requirements, or you need to move to a SIMPLE IRA. Planning for this transition before it happens, rather than scrambling after, avoids penalties and administrative disruption.

Layering an IRA on Top of a Self-Employed Plan

Contributing to a Solo 401(k) or SEP-IRA does not automatically disqualify you from also funding a traditional or Roth IRA, though income limits and deductibility rules apply. For 2025, the IRA contribution limit is $7,000 ($8,000 for those age 50 and older), per current IRA contribution limits.

If your modified adjusted gross income falls within the Roth IRA eligibility range, funding a Roth IRA alongside a pre-tax Solo 401(k) creates a useful tax diversification. You draw down pre-tax Solo 401(k) funds in years when your income is lower, and you pull from the Roth IRA in years when avoiding additional taxable income is valuable. This kind of sequencing can meaningfully reduce lifetime tax costs, though the math depends on individual circumstances and is worth modeling with a tax advisor.

Frequently Asked Questions

What is the best retirement plan for self-employed people?

The Solo 401(k) is generally the best self employed retirement plan for sole proprietors earning more than $50,000 annually because it allows the highest contribution ceiling at $70,000 in 2025. SEP-IRAs are better for those who prioritize simplicity over maximum contribution capacity.

Can a self-employed person contribute to both a SEP-IRA and a Solo 401(k)?

No. You cannot maintain both a SEP-IRA and a Solo 401(k) for the same self-employment income in the same year. The IRS requires you to choose one plan type. You can also fund a separate traditional or Roth IRA in addition to either plan, subject to income limits.

When is the deadline to open a Solo 401(k) for this tax year?

The Solo 401(k) plan document must be established by December 31 of the tax year. Contributions, however, can be made up to your tax filing deadline, including extensions, which is typically October 15 for sole proprietors who file Form 1040 with a Schedule C.

How does a self-employed retirement plan reduce taxes?

Contributions to a traditional SEP-IRA or Solo 401(k) are deducted from gross income on your federal tax return, reducing your taxable income dollar for dollar. A $30,000 contribution in the 24% bracket reduces your federal tax bill by $7,200. Contributions do not, however, reduce self-employment tax.

What happens to my Solo 401(k) if I hire employees?

If you hire a full-time employee other than your spouse, your Solo 401(k) must convert to a standard 401(k) plan, which requires annual nondiscrimination testing and additional administrative costs. This transition point is when many business owners move to a SIMPLE IRA or work with a TPA to redesign the plan.

Can I roll over an old employer 401(k) into a Solo 401(k)?

Yes. Most Solo 401(k) plans accept rollovers from previous employer 401(k) plans and traditional IRAs. Rolling over old accounts consolidates your retirement savings and can simplify required minimum distribution calculations later. Verify that your Solo 401(k) plan document explicitly allows incoming rollovers before initiating the transfer.