What are the 2026 contribution limits for a Solo 401(k)?

In 2026, the Solo 401(k) total contribution limit is $70,000 (or $77,500 if you're 50 or older with catch-up contributions). This combines an employee elective deferral of up to $23,500 (or $31,000 for those 50+) plus employer profit-sharing contributions of up to 25% of net self-employment income. The combined total cannot exceed $70,000 or 100% of earned income, whichever is less.

Can I have both a Solo 401(k) and a SEP-IRA?

Generally not in the same tax year for the same self-employment income. You can maintain both accounts — for example, if you transition from one plan type to the other — but contributions in a given year are subject to the same overall limit of $70,000 across both plans. Some business owners who have a W-2 job with a 401(k) can contribute to a SEP-IRA for their self-employment income, but the limits interact. Your CPA can model which combination maximizes your total deduction.

Which retirement account is better for high-income self-employed individuals?

At high self-employment income levels (typically above $150,000 in net self-employment income), the Solo 401(k) almost always allows higher total contributions because of the employee deferral component. A self-employed person earning $200,000 in net income can contribute roughly $23,500 in employee deferrals plus approximately $37,500 in employer contributions under a Solo 401(k) versus only $50,000 under a SEP-IRA — and the Solo 401(k) total can exceed the SEP-IRA ceiling at many income levels.

Can I still contribute to a Solo 401(k) if I have employees?

No — the Solo 401(k) (also called an Individual 401(k)) is only available to self-employed individuals with no full-time employees other than a spouse. If you hire even one full-time employee (working 1,000+ hours per year), you must switch to a regular 401(k) plan or SIMPLE IRA. Part-time workers and independent contractors generally don't disqualify you. This is one of the most important eligibility points to monitor as your business grows.

When is the Solo 401(k) contribution deadline?

The employee elective deferral portion must be elected by December 31 of the tax year. The employer profit-sharing portion can be contributed by the tax filing deadline, including extensions (typically October 15 for sole proprietors). The plan itself must be established — meaning set up with a plan provider — by December 31 of the year you want to make contributions. Waiting until tax season to set up a new Solo 401(k) is a common mistake that costs business owners a full year of contribution capacity.

Solo 401(k) vs. SEP-IRA: Which Retirement Account Saves Small Business Owners More in 2026?

July 16, 2026 · Guide · 7 min read

For most self-employed individuals and single-owner businesses in 2026, the Solo 401(k) allows larger tax-deductible contributions than a SEP-IRA at the same income level — often meaningfully so. On $150,000 of net self-employment income, a Solo 401(k) allows a total contribution of roughly $56,000, while a SEP-IRA caps at $37,500. Over a decade, that difference compounds into a substantial gap in retirement assets and current-year tax deductions. The question of which account is right isn't purely about the math, though — eligibility, administrative requirements, and your specific business situation all shape the decision.

The Foundational Difference: How Each Account Is Funded

A SEP-IRA (Simplified Employee Pension) is funded entirely with employer contributions — in the self-employed context, that means contributions from your business. The annual limit is 25% of net self-employment income (after the self-employment tax deduction), up to a dollar ceiling of $70,000 in 2026. The mechanics are simple: your CPA calculates 25% of your eligible compensation, you contribute that amount by the tax filing deadline, and you deduct it.

A Solo 401(k) — also called an Individual 401(k) or One-Participant 401(k) — is funded from two separate buckets. First, you contribute as an "employee" (yourself), deferring up to $23,500 of your income in 2026 (or $31,000 if you're 50 or older, with catch-up provisions). Second, you contribute as the "employer," adding profit-sharing contributions of up to 25% of net self-employment income. Both contributions count toward the same annual ceiling of $70,000, but the employee deferral component is what gives the Solo 401(k) its contribution advantage at moderate income levels — you can maximize that deferral even when your business profit margins aren't high enough to generate a large 25% employer contribution.

Contribution Limits Compared in 2026

SEP-IRA: The Simpler Formula

The SEP-IRA contribution formula is: net self-employment income minus half of self-employment tax, multiplied by 20% (which equals 25% of net compensation after adjustments). At $80,000 of net self-employment income, this allows approximately $14,800 in contributions. At $200,000, it allows approximately $37,000. At $280,000, you hit the dollar ceiling of $70,000. These calculations assume you're operating as a sole proprietor or single-member LLC; S-corp owners calculate their contribution based on W-2 wages paid to themselves rather than business profits, which creates a different optimization problem.

Solo 401(k): Where the Advantage Appears

At the same $80,000 net income, a Solo 401(k) allows approximately $23,500 in employee deferrals plus approximately $14,800 in employer contributions — a total of roughly $38,300 versus the SEP-IRA's $14,800. The entire advantage at this income level comes from the employee deferral component. At $200,000 net income, the Solo 401(k) total is approximately $60,500 versus the SEP-IRA's $37,000. The gap narrows as income rises and the employer contribution component grows, and the two accounts converge near the dollar ceiling of $70,000 — both reach that limit at around $280,000 of net income, though the Solo 401(k) reaches it earlier due to the employee deferral boost.

When the Solo 401(k) Is the Clear Choice

Choose the Solo 401(k) if: your net self-employment income is under $230,000 and you want to maximize contributions, you want the ability to make Roth contributions (SEP-IRAs don't allow Roth deferrals; many Solo 401(k) providers now offer a Roth component), you want the option to borrow against your retirement savings in an emergency, or you want to consolidate old 401(k)s from previous employers via a rollover into your plan. Solo 401(k)s accept rollovers; SEP-IRAs also accept rollovers, but there are tax considerations with certain rollover types.

The Roth component is increasingly valuable in tax planning. A Roth Solo 401(k) contribution is made with after-tax dollars, grows tax-free, and is withdrawn tax-free in retirement — a strong choice if you expect to be in a higher tax bracket in retirement or if you want flexibility in managing retirement income distributions. Your CPA can model the after-tax value of Roth versus traditional contributions at your current and projected tax rates.

When the SEP-IRA Makes More Sense

The SEP-IRA has real advantages in specific situations: it can be established and funded all the way until the tax filing deadline of the contribution year, including extensions. A Solo 401(k) must be established by December 31 of the tax year — if you're setting up a retirement plan for the first time in March while preparing your taxes, the SEP-IRA is the only option for the prior tax year. This deadline difference alone accounts for why many self-employed individuals start with a SEP-IRA.

The SEP-IRA is also simpler to administer — no annual Form 5500-EZ filing, no IRS reporting requirements until the plan exceeds $250,000 in assets (and even then the filing is minimal), and straightforward contribution mechanics. For business owners who want the smallest administrative footprint possible, this simplicity has real value. The SEP also allows you to contribute for employees, which makes it the right tool if you have workers who qualify for employer contributions under retirement plan rules.

The Solo 401(k) Loan Feature

One advantage the Solo 401(k) has that the SEP-IRA lacks: the ability to borrow from your own account. Solo 401(k) plans that include a loan provision allow you to borrow up to 50% of the vested account balance or $50,000, whichever is less. Loans must be repaid within five years (or longer if used for a primary home purchase) with interest — the interest you pay goes back into your own account rather than to a lender. This isn't a strategy to use casually, but it provides liquidity access that the SEP-IRA doesn't offer without triggering taxes and the 10% early withdrawal penalty.

Setup and Administration: What Each Actually Requires

A SEP-IRA is established by completing IRS Form 5305-SEP or using a provider's prototype plan document. Most major brokerages (Fidelity, Vanguard, Schwab) offer free SEP-IRA accounts with no ongoing maintenance fees. Contributions are made at the brokerage, invested in your chosen funds, and deducted on Schedule C or Form 1040 via Form 5498. The process takes about an hour and requires no attorney or plan document customization.

A Solo 401(k) requires more upfront setup. You need an EIN (Employer Identification Number), a plan document from a plan provider, and to complete IRS Form 5500-EZ annually once plan assets exceed $250,000. Several providers (Fidelity, E*TRADE, TD Ameritrade) offer free Solo 401(k) plans with standard features. Custom plan documents with Roth provisions, loan features, or investment flexibility beyond standard brokerage offerings typically require a third-party administrator (TPA), which costs $200–$600 per year. The added complexity is worthwhile for most high-income self-employed individuals once you've confirmed eligibility and modeled the contribution advantage.

SIMPLE IRA: The Third Option Worth Knowing

If you have employees and want a retirement plan that's simpler than a full 401(k) but more generous than a SEP-IRA, the SIMPLE IRA allows employee contributions of up to $16,500 in 2026 (plus $3,500 catch-up for those 50+) with mandatory employer matching of 2–3%. It's easier to administer than a standard 401(k) but doesn't allow the high contribution levels of the Solo 401(k). The SIMPLE IRA is most appropriate for small businesses with a handful of employees where the owner wants to provide a retirement benefit without the plan documentation overhead of a full 401(k).

Getting Your CPA Involved Before Choosing

The right account depends on your net self-employment income, business entity type, whether you have employees, your age, and your current versus projected tax brackets. A CPA who works with self-employed clients regularly can model the exact contribution difference at your income level, confirm your eligibility for each account type, and integrate the retirement contribution decision with your broader tax strategy — including how retirement contributions interact with the Qualified Business Income (QBI) deduction, estimated tax payments, and your S-corp salary if you've elected S-corp treatment.

Our guide to tax planning strategies for the self-employed covers how retirement account contributions fit into an overall year-round tax strategy. For S-corp owners and startup founders navigating equity and entity structure alongside retirement planning, our CPA for startups guide addresses these intersecting decisions. The 1099 vs. W-2 guide covers how your employment classification affects which plan types are available and how contributions are calculated. Browse CPAs by city to find tax professionals near you who specialize in self-employed retirement planning, or search for CPAs near you with specific small business tax experience.

Frequently Asked Questions

What are the 2026 contribution limits for a Solo 401(k)?: In 2026, the Solo 401(k) total contribution limit is $70,000 (or $77,500 if you're 50 or older with catch-up contributions). This combines an employee elective deferral of up to $23,500 (or $31,000 for those 50+) plus employer profit-sharing contributions of up to 25% of net self-employment income. The combined total cannot exceed $70,000 or 100% of earned income, whichever is less.
Can I have both a Solo 401(k) and a SEP-IRA?: Generally not in the same tax year for the same self-employment income. You can maintain both accounts — for example, if you transition from one plan type to the other — but contributions in a given year are subject to the same overall limit of $70,000 across both plans. Some business owners who have a W-2 job with a 401(k) can contribute to a SEP-IRA for their self-employment income, but the limits interact. Your CPA can model which combination maximizes your total deduction.
Which retirement account is better for high-income self-employed individuals?: At high self-employment income levels (typically above $150,000 in net self-employment income), the Solo 401(k) almost always allows higher total contributions because of the employee deferral component. A self-employed person earning $200,000 in net income can contribute roughly $23,500 in employee deferrals plus approximately $37,500 in employer contributions under a Solo 401(k) versus only $50,000 under a SEP-IRA — and the Solo 401(k) total can exceed the SEP-IRA ceiling at many income levels.
Can I still contribute to a Solo 401(k) if I have employees?: No — the Solo 401(k) (also called an Individual 401(k)) is only available to self-employed individuals with no full-time employees other than a spouse. If you hire even one full-time employee (working 1,000+ hours per year), you must switch to a regular 401(k) plan or SIMPLE IRA. Part-time workers and independent contractors generally don't disqualify you. This is one of the most important eligibility points to monitor as your business grows.
When is the Solo 401(k) contribution deadline?: The employee elective deferral portion must be elected by December 31 of the tax year. The employer profit-sharing portion can be contributed by the tax filing deadline, including extensions (typically October 15 for sole proprietors). The plan itself must be established — meaning set up with a plan provider — by December 31 of the year you want to make contributions. Waiting until tax season to set up a new Solo 401(k) is a common mistake that costs business owners a full year of contribution capacity.