The 2026 solo 401(k) contribution limits allow a combined $72,000, from a $24,500 employee deferral plus employer profit-sharing of up to 25% of compensation, rising to $80,000 or $83,250 with age-based catch-ups.
Key Takeaways
- The combined 2026 solo 401(k) limit is $72,000 (section 415(c)), up from $70,000 in 2025 (Source: IRS Notice 2025-67).
- The employee elective deferral is $24,500 for 2026, up from $23,500 in 2025, and is a single per-person ceiling across all 401(k) plans.
- An $8,000 catch-up at ages 50 to 59 raises the total to $80,000, and an $11,250 super catch-up at ages 60 to 63 raises it to $83,250.
- The employer profit-sharing contribution is up to 25% of compensation, which converts to an effective 20% for a sole proprietor because 0.25 divided by 1.25 equals 0.20.
- A sole proprietor needs about $237,500 of net self-employment earnings to reach the full $72,000, while an S-corporation owner reaches it at $190,000 of W-2 wages.
- Starting in 2026, catch-up contributions must be Roth for participants whose prior-year FICA wages exceeded $150,000 (Source: IRS Notice 2025-67, section 414(v)(7)).
- The compensation cap is $360,000 for 2026, and Form 5500-EZ is generally required once plan assets exceed $250,000.
2026 Solo 401(k) Limits At A Glance
Figures apply to the 2026 tax year. Catch-up contributions of $8,000 (ages 50 to 59) or $11,250 (ages 60 to 63) sit on top of the combined limit.
The 2026 solo 401k contribution limits let a self-employed owner contribute up to $72,000, combining a $24,500 employee salary deferral with an employer profit-sharing contribution of up to 25% of compensation (Source: IRS Notice 2025-67). Age-based catch-up contributions push the ceiling to $80,000 or $83,250. This guide shows the exact figures plus the self-employed math, including the S-corporation versus sole-proprietor calculation, that most articles skip.
For 2026, a solo 401(k) participant can contribute up to $24,500 as an employee elective deferral plus an employer profit-sharing contribution, for a combined limit of $72,000 before catch-ups (Source: IRS Notice 2025-67). Adding the age 50 to 59 catch-up of $8,000 raises the total to $80,000; the age 60 to 63 super catch-up of $11,250 raises it to $83,250.
What are the 2026 solo 401(k) contribution limits?
The 2026 solo 401(k) contribution limit is $72,000 combined, or $80,000 with the age 50 to 59 catch-up and $83,250 with the age 60 to 63 super catch-up (Source: IRS Notice 2025-67). That $72,000 combines a $24,500 employee deferral and an employer profit-sharing contribution of up to 25% of compensation. A solo 401(k) has two contribution sources in one account: the owner as employee and the same owner as employer.
A solo 401(k), also called a one-participant 401(k), Solo-k, or Uni-k, is a traditional 401(k) covering a business owner with no employees, or that owner and a spouse (Source: IRS, One-participant 401(k) plans). The table below shows each 2026 figure next to 2025. Every dollar amount comes from IRS Notice 2025-67.
| Contribution component | 2026 | 2025 |
|---|---|---|
| Employee elective deferral (section 402(g)) | $24,500 | $23,500 |
| Catch-up, age 50 to 59 and 64 plus (section 414(v)) | $8,000 | $7,500 |
| Super catch-up, age 60 to 63 (SECURE 2.0) | $11,250 | $11,250 |
| Employer profit-sharing | Up to 25% of compensation | Up to 25% of compensation |
| Combined limit, no catch-up (section 415(c)) | $72,000 | $70,000 |
| Combined with age 50 to 59 catch-up | $80,000 | $77,500 |
| Combined with age 60 to 63 super catch-up | $83,250 | $81,250 |
| Annual compensation cap (section 401(a)(17)) | $360,000 | $350,000 |
The $72,000 figure is the section 415(c) annual additions limit, up from $70,000 in 2025. Catch-up contributions sit on top of that limit rather than inside it, which is why the age 50 plus totals of $80,000 and $83,250 exceed $72,000.
How much can I contribute as the employee for 2026?
As the employee, you can defer up to $24,500 in 2026, up from $23,500 in 2025 (Source: IRS Notice 2025-67, section 402(g)(1)). This limit is per person, not per plan. If you participate in more than one 401(k) in the same year, the $24,500 ceiling applies across all of them combined. You also cannot defer more than you earn, since deferrals are capped at 100% of compensation.
For a self-employed owner, the earned income used for the 100% test is net earnings from self-employment, so a business with modest net earnings may hit an earnings limit before reaching the dollar cap. The per-person rule matters most for owners who also hold a day job with an employer 401(k), covered below.
What are the 2026 catch-up contributions by age?
For 2026, the catch-up contribution is $8,000 for participants age 50 to 59 and age 64 plus, up from $7,500 in 2025 (Source: IRS Notice 2025-67, section 414(v)). A larger super catch-up of $11,250 applies at ages 60, 61, 62, and 63 under SECURE 2.0. The super catch-up replaces the $8,000 figure for those four ages rather than stacking on it.
A participant age 50 or older can therefore defer up to $32,500 as the employee ($24,500 plus $8,000) before employer contributions, rising to $35,750 at ages 60 to 63 ($24,500 plus $11,250). At age 64 and beyond, the catch-up reverts to the standard $8,000.
How is the employer profit-sharing contribution calculated?
The employer contribution is up to 25% of compensation (Source: IRS, One-participant 401(k) plans). What counts as compensation, and therefore how the 25% is applied, differs sharply between an S-corporation owner paid W-2 wages and a sole proprietor or single-member LLC taxed on net self-employment income. The two worked examples below show why the S-corporation uses a straight 25% while the sole proprietor uses an effective 20%.
S-corporation owner: a straight 25% of W-2 wages
For an owner who takes W-2 wages from an S-corporation, the employer contribution is a straight 25% of those wages, with no self-employment-tax adjustment. If the owner is paid $100,000 in W-2 wages, the employer profit-sharing contribution can be up to $25,000. Add the $24,500 employee deferral and the combined 2026 contribution reaches $49,500, still under the $72,000 overall limit (Source: IRS Notice 2025-67 for the dollar limits).
Sole proprietor or single-member LLC: the effective 20% rate
For a sole proprietor or single-member LLC, the 25% plan rate converts to an effective self-employed rate of 20% (Source: IRS Publication 560, 2025). The reduction happens because the contribution is itself deductible, so the 25% is applied to compensation after that contribution is removed: 0.25 divided by 1.25 equals 0.20. The 20% applies to net earnings from self-employment, defined as net profit reduced by the half-SE-tax deduction and by the contribution itself.
The step-by-step order is:
- Start with net profit from the business (Schedule C).
- Subtract the deduction for one-half of self-employment tax to reach net earnings from self-employment.
- Apply the effective 20% rate to that net-earnings figure for the maximum employer profit-sharing contribution.
- Add the employee deferral (up to $24,500 for 2026, or more with catch-up), subject to the $72,000 overall limit.
As an illustration, suppose net earnings from self-employment (after the half-SE-tax deduction) work out to $100,000. The employer profit-sharing contribution can be up to $20,000, and adding the $24,500 employee deferral gives a combined 2026 contribution of $44,500. Publication 560 supplies a Rate Worksheet and Deduction Worksheet for the Self-Employed to run the exact numbers. Compensation counted for the employer contribution is capped at $360,000 for 2026 (Source: IRS Notice 2025-67, section 401(a)(17)).
How much net income do I need to max out a solo 401(k) in 2026?
A sole proprietor needs roughly $238,000 of net earnings from self-employment (after the half-SE-tax deduction) to reach the full $72,000 in 2026. The math: $72,000 minus the $24,500 employee deferral leaves $47,500 to fund from the employer side, and $47,500 divided by the effective 20% rate equals $237,500 (Source: IRS Notice 2025-67; IRS Publication 560, 2025). An S-corporation owner reaches the same $72,000 at $190,000 of W-2 wages ($47,500 divided by 0.25).
| Entity type | Employer rate | Income needed for max | How the $72,000 is built |
|---|---|---|---|
| Sole proprietor / single-member LLC | Effective 20% of net SE earnings | About $237,500 net SE earnings | $24,500 deferral plus $47,500 employer |
| S-corporation owner | 25% of W-2 wages | $190,000 W-2 wages | $24,500 deferral plus $47,500 employer |
For a sole proprietor, the Schedule C net profit needed is somewhat higher than $237,500, because the half-SE-tax deduction is subtracted before the 20% is applied. Owners below these income levels are limited by the percentage-of-compensation math rather than by the $72,000 cap.
Can I have a solo 401(k) and a day-job 401(k)?
Yes. You can hold a solo 401(k) for a side business and also participate in an employer 401(k) at a full-time job. Only the employee deferral is shared: the $24,500 limit for 2026 is a single per-person ceiling across every 401(k) you hold (Source: IRS Notice 2025-67, section 402(g)(1)). The employer profit-sharing contribution is separate and is not shared between the two plans.
Here is the piece most articles mention but rarely quantify. Suppose your day-job 401(k) absorbs the entire $24,500 employee deferral. Your solo 401(k) can still receive the employer profit-sharing contribution from the side business, up to that plan’s own $72,000 limit. A sole proprietor with $100,000 of net SE earnings could still direct up to $20,000 in employer contributions to the solo plan even after the deferral is used elsewhere.
Coordinating multiple accounts interacts with wider tax planning, since contributions lower current adjusted gross income and shape future required distributions, as covered in the Q3 Advisors guide to required minimum distributions for 2026.
How does the 2026 Roth catch-up mandate affect solo 401(k) owners?
Starting in 2026, catch-up contributions must be made as Roth for participants whose prior-year FICA wages exceeded $150,000 (Source: IRS Notice 2025-67, section 414(v)(7); threshold increased from $145,000). For solo 401(k) owners, this mostly affects S-corporation owners who take W-2 wages above that level, because the rule keys off FICA wages, which are the wages subject to Social Security and Medicare tax.
Two nuances go unexplained on most pages. First, a sole proprietor with no W-2 wages generally has no FICA wages of the type the rule references and may fall outside it, though that determination depends on individual circumstances. Second, if a plan does not offer a Roth source, an affected high earner may be unable to make the catch-up at all until the plan document adds one.
Many solo 401(k) plans allow a Roth source for employee deferrals, and SECURE 2.0 also permits Roth employer contributions where a plan offers them. For owners weighing after-tax retirement dollars, Q3 Advisors describes its Roth conversion service and explains how much to convert to Roth.
What are the deadlines to open and fund a solo 401(k)?
Employer profit-sharing contributions can generally be made up to the business tax-filing deadline, including extensions. Employee deferral elections have their own timing rules that often require the election to be in place earlier in the year, so the two sources do not always share the same cutoff (Source: IRS, One-participant 401(k) plans).
Plan adoption has a separate rule. A solo 401(k) historically had to be established by December 31 of the plan year. Under SECURE 2.0 Section 317, a sole proprietor may in some cases adopt a plan after year-end and treat it as effective for the prior year up to the tax-filing deadline, which can affect first-year employer contributions. Deferral elections generally still require the plan to exist during the year, so this relief is narrower than it first appears.
Solo 401(k) vs SEP IRA: which lets me contribute more?
For most self-employed owners, a solo 401(k) allows a larger contribution at the same income because it adds a $24,500 employee deferral on top of the employer contribution, while a SEP IRA offers only the employer-style contribution of up to 25% of compensation (effective 20% for a sole proprietor). Both share the same $72,000 overall ceiling for 2026, but the solo 401(k) reaches it at lower income.
At $100,000 of net SE earnings, a sole proprietor’s SEP IRA allows about $20,000, while the solo 401(k) allows about $44,500 once the $24,500 deferral is added. The SEP IRA can be simpler to administer, with no Form 5500 filing. For a fuller side-by-side, see the Q3 Advisors comparison of the SEP IRA versus solo 401(k).
Spouse participation and Form 5500-EZ
A spouse who earns income from the same business can also participate, because a solo 401(k) covers a business owner or that person and a spouse (Source: IRS, One-participant 401(k) plans). Each spouse has a separate $24,500 employee deferral limit for 2026 and can receive an employer contribution, which can roughly double the household contribution capacity within the plan.
Once total plan assets exceed $250,000, the plan generally must file Form 5500-EZ annually with the IRS. Below that threshold, a one-participant plan is typically exempt, though a final Form 5500-EZ is generally required when the plan terminates. Because these filing rules interact with broader tax timing, some owners review them alongside their net investment income tax exposure for 2026.
Work with Q3 Advisors
Q3 Advisors is a registered investment adviser focused on retirement tax planning. This page is educational and is not advice; consult a qualified professional.
Frequently asked questions
How much can I contribute to a Solo 401(k) in 2026?
For 2026, the combined limit is $72,000, made up of a $24,500 employee deferral plus an employer profit-sharing contribution of up to 25% of compensation (Source: IRS Notice 2025-67). Catch-up contributions raise the ceiling to $80,000 at ages 50 to 59 and 64 plus, and to $83,250 at ages 60 to 63. Actual amounts depend on the owner’s compensation.
Can you have a Solo 401(k) and a regular 401(k)?
Yes. The rules allow both, but the $24,500 employee deferral limit for 2026 is shared across all 401(k) plans per person (Source: IRS Notice 2025-67). The solo 401(k) employer profit-sharing contribution is separate and remains available even if a day-job 401(k) uses the full deferral, up to the $72,000 overall limit for the solo plan.
How is the Solo 401(k) employer contribution calculated for self-employed?
For a sole proprietor, the 25% plan rate equals an effective 20% of net earnings from self-employment after the half-SE-tax deduction, because 0.25 divided by 1.25 equals 0.20 (Source: IRS Publication 560, 2025). For an S-corporation owner, the employer contribution is a straight 25% of W-2 wages, with no self-employment-tax adjustment.
What is the deadline to open a Solo 401(k)?
A solo 401(k) traditionally had to be established by December 31 of the plan year. Under SECURE 2.0 Section 317, a sole proprietor may in some cases adopt a plan after year-end, effective for the prior year up to the tax-filing deadline (Source: IRS, One-participant 401(k) plans). Employer contributions can generally be made up to the filing deadline, including extensions.
Can I contribute to both a Solo 401(k) and a SEP IRA?
The two can technically coexist, but if both cover the same business, the combined employer-type contributions are generally limited by the same $72,000 section 415(c) ceiling for 2026 and the compensation-based percentage rules (Source: IRS Notice 2025-67; IRS Publication 560, 2025). Running both for one business rarely adds capacity. The right structure depends on individual facts.
How much net income do I need to max out a Solo 401(k)?
A sole proprietor needs about $237,500 of net earnings from self-employment (after the half-SE-tax deduction) to reach the full $72,000 in 2026, because $72,000 minus the $24,500 deferral leaves $47,500, and $47,500 divided by 20% equals $237,500 (Source: IRS Notice 2025-67; IRS Publication 560, 2025). An S-corporation owner reaches it at $190,000 of W-2 wages.
