Solo 401k Contribution Limits
Understand the annual limits for your Solo 401k contributions
A Solo 401k offers the highest contribution limits of any retirement plan available to self-employed individuals. Below is a quick summary of the 2025 and 2026 limits, followed by a deeper explanation of how the two contribution buckets (employee deferral + employer profit-sharing) combine, a year-over-year comparison going back to 2023, and answers to the most common questions. Need an actual number for your situation? Use the Solo 401k Contribution Calculator.
Under Age 50
| Contribution Type | 2025 | 2026 |
|---|---|---|
| Employee Contribution | $23,500 | $24,500 |
| Total Contribution Limit | $70,000 | $72,000 |
Age 50 and Older
| Contribution Type | 2025 | 2026 |
|---|---|---|
| Employee Contribution | $23,500 | $24,500 |
| Catch-up Contribution | +$7,500 | +$8,000 |
| Total Employee Contribution | $31,000 | $32,500 |
| Total Contribution Limit | $77,500 | $80,000 |
Age 60-63
Note: Ages 60–63 have an enhanced catch-up limit of $11,250 per SECURE 2.0
| Contribution Type | 2025 | 2026 |
|---|---|---|
| Employee Contribution | $23,500 | $24,500 |
| Catch-up Contribution | +$11,250 | +$11,250 |
| Total Employee Contribution | $34,750 | $35,750 |
| Total Contribution Limit | $81,250 | $83,250 |
How Solo 401k contribution limits work
Solo 401k contributions come in two parts because, as the self-employed plan sponsor, you contribute as both employee and employer. The annual IRS limits set the maximum for each part independently, plus a combined total. Understanding which bucket you're filling is the key to actually hitting the maximum.
The employee deferral (elective deferral)
The employee deferral is the same limit that applies to anyone with a 401k — $24,500 in 2026 (up from $23,500 in 2025 and $23,000 in 2024). This limit is per person across all 401k plans, so if you also have a W-2 day job and are deferring into that employer's 401k, your Solo 401k deferral capacity is reduced by whatever you defer at the day job.
You can split the deferral between pre-tax and Roth, depending on whether your Solo 401k provider supports a Roth option. Most major providers do.
The employer profit-sharing contribution
On top of the employee deferral, your business contributes a profit-sharing amount. The percentage depends on your business structure:
- Sole proprietors and single-member LLCs: up to 20% of net self-employment income (Schedule C profit minus the deductible half of self-employment tax). The 20% is the algebraic equivalent of "25% of compensation" once you back out the contribution itself.
- S-Corp and C-Corp owners: up to 25% of your W-2 wages. Distributions and K-1 pass-through income do not count toward this calculation.
The employer side is where the Solo 401k gets its high total contribution limit. Maximum compensation that can be considered for the employer formula is capped at $350,000 in 2026 ($350,000 in 2025; $345,000 in 2024).
Catch-up contributions and the SECURE 2.0 super catch-up
If you're 50 or older, you can add a catch-up contribution to the standard employee deferral — $8,000 in 2026 (up from $7,500 in 2024 and 2025). The SECURE 2.0 Act introduced a higher "super catch-up" specifically for ages 60-63: $11,250 in both 2025 and 2026, instead of the standard catch-up. At age 64+, you revert to the standard catch-up amount.
Starting in 2026, SECURE 2.0 also requires that catch-up contributions made by participants whose prior-year wages exceeded $145,000 (indexed) be designated Roth, if the plan supports Roth catch-ups. This is a "Rothification" rule aimed at high earners.
Year-over-year contribution limits (2023-2026)
Compare Solo 401k contribution limits across the last four tax years. Use the earlier-year rows if you're funding a prior-year contribution.
| Limit | 2023 | 2024 | 2025 | 2026 |
|---|---|---|---|---|
| Employee deferral (under 50) | $22,500 | $23,000 | $23,500 | $24,500 |
| Catch-up (age 50-59, 64+) | $7,500 | $7,500 | $7,500 | $8,000 |
| Super catch-up (age 60-63) | N/A | N/A | $11,250 | $11,250 |
| Total contribution (under 50) | $66,000 | $69,000 | $70,000 | $72,000 |
| Total contribution (age 50-59, 64+) | $73,500 | $76,500 | $77,500 | $80,000 |
| Total contribution (age 60-63) | N/A | N/A | $81,250 | $83,250 |
| Max compensation considered | $330,000 | $345,000 | $350,000 | $350,000 |
Sources: IRS Notice 2022-55 (2023), IRS Notice 2023-75 (2024), IRS Notice 2024-80 (2025), IRS Notice 2025-67 (2026). The age 60-63 super catch-up was created by the SECURE 2.0 Act and first applied in 2025.
Contribution deadlines
Solo 401k contribution deadlines depend on which bucket (employee or employer) you're funding and your business entity.
- Employee deferral election: must be made by December 31 of the tax year. S-Corp owners typically need to actually withhold the deferral through payroll by year-end; sole proprietors generally have until their tax filing deadline to fund the elected deferral.
- Employer profit-sharing — S-Corp / C-Corp: can be funded up to your corporate tax filing deadline, March 15, or September 15 with a filed extension.
- Employer profit-sharing — sole proprietor / single-member LLC: can be funded up to your personal tax filing deadline, April 15, or October 15 with a filed extension.
- Plan adoption deadline: SECURE Act Section 201 lets you adopt a Solo 401k as late as your tax filing deadline (including extensions) and still make employer contributions for the prior year. Employee deferrals, however, still require a year-end election if you want to make them for that tax year.
Solo 401k contribution limit FAQs
How much can I contribute to a Solo 401k?
You can contribute as both employee and employer. In 2026, the employee deferral limit is $24,500 and the total combined limit is $72,000 — rising to $80,000 if you are 50-59 or 64+, or $83,250 if you are 60-63 (under the SECURE 2.0 super catch-up). The employer portion is up to 20% of net self-employment income for sole proprietors or 25% of W-2 wages for S-Corp owners.
What are the Solo 401k contribution limits for 2026?
For 2026, the Solo 401k employee deferral limit is $24,500. Catch-up contributions are $8,000 for ages 50-59 and 64+, or $11,250 for ages 60-63. Total contribution limits are $72,000 (under 50), $80,000 (ages 50-59 and 64+), and $83,250 (ages 60-63). The maximum compensation that can be considered for the employer profit-sharing calculation is capped at $350,000.
What are the Solo 401k contribution limits for 2025?
For 2025, the Solo 401k employee deferral limit was $23,500. Catch-up contributions were $7,500 for ages 50-59 and 64+, or $11,250 for ages 60-63. Total contribution limits were $70,000 (under 50), $77,500 (ages 50-59 and 64+), and $81,250 (ages 60-63). 2025 employer profit-sharing contributions can still be funded up until your tax filing deadline including extensions.
What is the max Solo 401k contribution for 2025?
The maximum Solo 401k contribution for 2025 was $70,000 if under 50, $77,500 with the standard age 50+ catch-up, and $81,250 for ages 60-63 under the SECURE 2.0 super catch-up. To hit the maximum, you generally need around $215,000+ of compensation as an S-Corp owner (25% of W-2) or roughly $230,000+ of net self-employment income as a sole proprietor (20% formula).
How are Solo 401k contribution limits different from a regular 401k?
The employee deferral limit is the same as a regular employer-sponsored 401k ($24,500 in 2026), and that limit is shared across all 401k plans you participate in. The big difference is the employer side: a Solo 401k lets you make a profit-sharing contribution as the business owner — up to 20% of net SE income or 25% of W-2 wages — on top of your deferral. That is why Solo 401k total limits ($72,000+) are so much higher than what a typical employee can contribute alone.
Are Solo 401k contribution limits per person or per couple if married filing jointly?
Solo 401k contribution limits are per person, not per household. If your spouse earns income from the same business, they can have their own Solo 401k account under the same plan and contribute up to the full annual limit ($72,000 in 2026, before catch-ups), effectively doubling the household total. Filing status (married filing jointly vs. single) does not change the contribution limits themselves — those are set by the IRS at the individual level.
Did the SECURE 2.0 Act change Solo 401k contribution limits?
Yes, in two ways. First, starting in 2025, ages 60-63 get a higher 'super catch-up' contribution — $11,250 in 2025 and 2026, vs. the standard $7,500/$8,000 catch-up. Second, beginning in 2026, catch-up contributions made by participants whose prior-year wages exceeded $145,000 (indexed) must be made on a Roth basis if the plan supports Roth catch-ups. These changes are fully implemented in the 2026 IRS limits.
When is the deadline to make Solo 401k contributions?
Employee deferrals must generally be elected by December 31 of the tax year (S-Corp owners must have payroll-withhold them by year-end). Employer profit-sharing contributions can be made up until your tax-filing deadline including extensions — March 15 (or September 15 with extension) for S-Corps, and April 15 (or October 15 with extension) for sole proprietors. This means you can still make a 2025 employer profit-sharing contribution well into 2026.
Detailed Year Guides
Select a year to view comprehensive contribution guidelines, including employer contributions, calculation methods, and practical examples:
2026 Contribution Limits
Explore the updated 2026 Solo 401k contribution limits, including the latest IRS adjustments for inflation.
2025 Contribution Limits
View the complete guide to 2025 Solo 401k contribution limits, including employee deferrals, employer contributions, and catch-up provisions.
2024 Contribution Limits
Review the 2024 Solo 401k contribution limits for tax year 2024 filings and historical reference.