You Work for Yourself. Your Retirement Account Should Too.
If you work for yourself — as a freelancer, consultant, independent contractor, or small business owner — you may be leaving one of the most powerful retirement savings tools on the table if you don't have a Solo 401(k). This guide covers how it works, who qualifies, what the contribution limits are, and how it compares to the SEP IRA.
Here's the simple version
When you work for a company, your employer sets up a 401(k). You contribute from your paycheck. They might match a portion. The government lets you defer taxes on the whole thing. It's one of the best deals in the tax code.
When you work for yourself, nobody sets that up for you. Most self-employed people default to a SEP IRA or a regular Roth IRA and call it a day — not because those are the best options, but because they're the most obvious ones.
The Solo 401(k) — also called an Individual 401(k) or one-participant 401(k) — is what happens when you set up that employer-sponsored 401(k) for yourself. Because you're both the employer and the employee in your own business, you get to contribute from both sides. That's the whole game.
The result: in 2026, you can shelter up to $72,000 from taxes in a single year — and potentially more if you're over 50. That's not a typo, and it's not a loophole. It's what the account is specifically designed to do.
Who can actually use one
The Solo 401(k) has one real restriction: you can't have employees. Specifically, no full-time employees other than yourself and, if applicable, your spouse. That's it.
If you're a freelancer, independent consultant, contractor, coach, real estate agent, photographer, designer, therapist in private practice, or really any solo operator — you almost certainly qualify. You don't need a formal business entity. A sole proprietor filing Schedule C works. So does an LLC, S-corp, C-corp, or partnership with no staff.
Freelancers who hire independent contractors are generally fine — contractors aren't common-law employees, and they don't affect your eligibility. The line gets drawn when you hire W-2 employees who work for you regularly under your direction.
One more nuance worth knowing: if you have a day job, you can still use a Solo 401(k) for your side income. Your employer's 401(k) and your Solo 401(k) are separate. The employee deferral limit ($24,500 in 2026) applies across both plans combined — so you can't double-dip on the employee side. But the employer profit-sharing contribution from your self-employment income is calculated independently and isn't affected by your day job contributions at all.
What about hiring someone later?
If you eventually bring on a full-time employee — someone working 1,000+ hours a year — your plan stops qualifying as a Solo plan and you'd need to transition to a standard 401(k). Under SECURE 2.0 (effective 2025), even part-time workers who've clocked 500+ hours for two years in a row must be allowed to participate. If you think you might scale up, flag this with your tax advisor before it becomes a compliance issue — not after.
The numbers
Here's where it gets interesting. You have two contribution slots every year: one as the employee, one as the employer. They're calculated separately and stack on top of each other.
Your employee contribution: up to $24,500 in 2026
As the "employee" of your own business, you can defer up to $23,500 of your income in 2025 — rising to $24,500 in 2026 — pre-tax, Roth, or a mix of both. This comes straight off your taxable income if you go the traditional route. And unlike the employer side, it's not a percentage game. You earn $60,000 this year? You can still put in $24,500 as an employee deferral. That flat dollar amount is what makes this account so powerful at moderate income levels.
One catch: the deferral limit applies across every 401(k) you participate in, not per plan. If you max out a 401(k) at your day job, you can't stack another $24,500 on the Solo side. But the employer contribution from your self-employment income? Completely separate — and still available to you in full.
If you're over 50, pay attention
SECURE 2.0 introduced a new age-tiered catch-up structure in 2025 that most people haven't heard of yet — and the numbers are surprisingly good depending on where you are in your 50s and 60s.
If you're between 50 and 59, or 64 and older, you can add a $7,500 catch-up on top of the base deferral, bringing your total employee contribution to $31,000 in 2025 and $32,500 in 2026. But if you happen to be 60, 61, 62, or 63, you get a bigger window: an $11,250 enhanced catch-up, for a total employee contribution of $34,750 in 2025. In 2026, that enhanced catch-up stays at $11,250, putting the total at $35,750 for that age bracket. Congress designed the 60–63 window specifically for the years right before most people retire, when you're typically earning more than ever and want to get as much into a tax-sheltered account as fast as possible. Your plan document needs to explicitly allow it — worth checking when you set up or review your plan.
HEADS UP FOR 2026 — ROTH CATCH-UP REQUIREMENT
Starting in the 2026 tax year, if you earned more than $145,000 in FICA wages in 2025, your catch-up contributions will be required to go into a Roth account (after-tax) rather than pre-tax. If your Solo 401(k) plan doesn't support Roth contributions, you may not be able to make catch-up contributions at all. This is the kind of thing worth discussing with your plan provider now, not when you're trying to make contributions next year. The threshold adjusts for inflation going forward.
Your employer contribution: up to 25% on top of that
After your employee deferral, you can also contribute as the employer — up to 25% of your compensation. In practice, if you're a sole proprietor or single-member LLC filing Schedule C, the math works out to roughly 20% of your net self-employment income. The IRS has a specific worksheet for this (Publication 560), and your CPA should run it — the exact number depends on your net income after deducting half of your self-employment tax.
If you run an S-corp and pay yourself a W-2 salary, the employer contribution is simply 25% of that salary. Cleaner math, which is one of several reasons some freelancers eventually elect S-corp status as their income grows.
The combined ceiling — and what it looks like in 2025 and 2026
Add the employee deferral and the employer profit-sharing together and you get the overall annual limit: $70,000 in 2025, rising to $72,000 in 2026. That's the cap for anyone under 50. If you're between 50 and 59 or 64 and older, the catch-up pushes that ceiling to $77,500 in 2025 and $80,000 in 2026. And if you're in that special 60–63 age window, your ceiling is $81,250 in 2025 and $83,250 in 2026. One additional note: the IRS caps the compensation used in all these calculations at $350,000 for 2025 and $360,000 for 2026 — so if you're earning above that, your employer contribution is calculated against those capped figures, not your full income.
Pre-tax or Roth — and why it matters more than you think
Unlike a SEP IRA, the Solo 401(k) lets you choose how your contributions are taxed. That flexibility is worth more than it sounds.
Traditional (pre-tax): You contribute before taxes, which lowers your taxable income today. You pay income tax when you withdraw the money in retirement. This is the classic play if you're in a high tax bracket now and expect to be in a lower one when you retire.
Roth (after-tax): You pay tax on the money now, at your current rate. After that, it grows tax-free, and qualified withdrawals in retirement are completely tax-free. No required minimum distributions during your lifetime (unlike traditional 401(k)s under pre-2024 rules). If you think tax rates are going up, or if you want flexibility in retirement, this is worth serious consideration.
A Solo 401(k) lets you split between both in any year — which means you can hedge. Put some in pre-tax when you have a high-income year. Go Roth when business is slower and your tax rate is lower. A SEP IRA gives you no such choice.
How to actually open one
This is the part where most people either procrastinate or get confused. Here's the honest version:
The deadline is real and non-negotiable. To use a Solo 401(k) for a given tax year, the plan must be established by December 31 of that year. You cannot open one in February and apply it to last year — that's the SEP IRA's trick, not this one's. If it's October and you're reading this, you still have time. If it's January, you're working toward next year.
Funding is more flexible. Once the plan is open, you can fund the employee deferral all the way through your tax filing deadline (April 15, or October 15 with an extension). The employer profit-sharing contribution can also be made up until that deadline. That means you can open the plan in December, then figure out the exact dollar amounts once your income is finalized.
One filing requirement to know about: When your plan's total assets cross $250,000, you're required to file Form 5500-EZ with the IRS each year. It's an informational return — not a tax payment — but skipping it triggers penalties. Most good plan providers track this for you.
Plans are available at major brokerages (Schwab, Fidelity, and others) and through specialized self-directed administrators. Features vary by provider — especially Roth availability, loan options, and after-tax contribution support. Don't just open the first one you find. Spend 20 minutes comparing what matters to you before committing.
The honest comparison with the SEP IRA
The SEP IRA is the other main option for self-employed people, and it gets recommended a lot — often because it's simpler to explain and open. That doesn't mean it's better. Here's where they actually differ, in plain English.
Contribution structure. This is the biggest one. A SEP IRA only takes employer contributions — there's no employee deferral component at all. That means every dollar you contribute is calculated as a percentage of your income, roughly 20% for sole proprietors. To hit the $70,000 cap in 2025, you'd need about $280,000 in net self-employment income. The Solo 401(k) lets you contribute $24,500 as the employee first — regardless of what the percentage math produces — and then add the employer portion on top. At $100,000 in income, that means roughly $42,000 total in a Solo 401(k) versus $18,500 in a SEP IRA. In 2026, the employee deferral rises to $24,500 and the overall cap moves to $72,000, so the structural advantage holds.
Catch-up contributions. The Solo 401(k) has them. The SEP IRA does not. If you're 50 or older, you can contribute an extra $8,000 on top of the $70,000 ceiling in 2026. The SEP IRA simply has no catch-up mechanism — what you see is what you get, regardless of your age.
Plan loans. If your plan document allows it, you can borrow from a Solo 401(k). A SEP IRA has no loan provision at all. Neither does a regular IRA.
Deadlines and administration. The SEP IRA wins on simplicity. You can open one and fund it right up to your tax filing deadline, including extensions — which means you could theoretically decide in October to fund a SEP IRA for the prior year. The Solo 401(k) plan must be established by December 31 of the tax year, and once your assets cross $250,000, you need to file Form 5500-EZ annually. None of that applies to a SEP IRA. It's genuinely less work.
If you have employees. The Solo 401(k) is only available if you have no full-time employees other than your spouse. If you have staff, the SEP IRA can cover them — though you're required to contribute the same percentage of compensation to each eligible employee's account that you contribute to your own. That rule becomes expensive as your team grows.
The spousal angle — potentially the best part
If your spouse works in your business and earns legitimate compensation for actual work performed, they can participate in the same Solo 401(k) under their own contribution limits. That means two employee deferrals. Two employer contributions. Potentially two sets of catch-up contributions if you're both over 50.
A couple running a business together, both maximizing contributions, can shelter a substantial combined amount from taxes in a single year. The operative word is "legitimate" — the compensation must reflect real work and be properly documented. This is not a situation to wing without talking to a tax professional first. But for couples where one spouse is already involved in the business, this is frequently one of the most underutilized planning opportunities available.
Before you open one, work through these
The Solo 401(k) is genuinely powerful but it's not for every situation. A few questions worth sitting with:
- Do you plan to hire anyone? Even one full-time W-2 employee other than your spouse and the Solo 401(k) is no longer available to you. If growth is in your plans, think ahead.
- What does your income look like this year? The employer contribution depends on your final net income. If your business is unpredictable, the flexible funding deadline helps — but you need to know the number eventually.
- Is it before December 31? That deadline for plan establishment is the one hard rule. Don't miss it and then wish you'd acted.
- Do you want Roth flexibility? Not all providers offer it. Choose your plan accordingly before you open it, not after.
- Do you already have a SEP IRA? You can roll a SEP IRA into a Solo 401(k), which some people do specifically to clean up the backdoor Roth math. Worth discussing with an advisor if that's relevant to your situation.
Questions about Solo 401(k)s? Our financial advisors are here to help—reach out anytime.
A NOTE ON THIS ARTICLE
The rules, limits, and deadlines above reflect current IRS guidance as of the publication date. Tax law changes, so verify figures at irs.gov or with a qualified CPA before making any decisions. This is educational content — it is not tax advice, and it doesn't account for your specific situation. Neptune Wealth doesn't provide tax advice. IRS Publication 560 is the primary reference for self-employed retirement plan rules. Our Form ADV Part 2, which describes our services, fees, conflicts of interest, and advisory practices in detail, is available at adviserinfo.sec.gov and on the SEC's Investment Adviser Public Disclosure website.
Educational content only.
This article is for informational and educational purposes and does not constitute investment advice or a recommendation of any specific strategy or service. All references to AI tools describe general capabilities of technology in the financial services industry; they do not represent performance guarantees or specific results for any client. Past performance is not indicative of future results. Investing involves risk, including possible loss of principal. Neptune Advisory LLC (d/b/a Neptune Wealth) is a Registered Investment Adviser in Pennsylvania, Florida, and Wisconsin. Please review our Form ADV Part 2 and disclosures before engaging our services.
