What are the maximum allowable contributions to a solo 401(k) in 2026?

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Casey Epton, CPA, is a Senior Tax Advisor at Deduction, where he helped design Taylor, CPAI from day one, building an AI tax agent that works seamlessly for both clients and the CPAs who verify every return.

Last updated:

Sep 2026

The maximum contribution to a solo 401(k) for 2026 is $72,000 for participants under age 50. Participants aged 50–59 and 64+ can contribute up to $80,000, and participants aged 60–63 can reach $83,250 under the SECURE 2.0 super catch-up provision. These figures represent the IRC §415(c) combined ceiling. Reaching the maximum requires both sufficient income and the right combination of employee deferrals and employer profit-sharing contributions.

Maximum Contribution by Age

Age Group	Employee Deferral	Max Employer Contribution	Total Maximum
Under 50	$24,500	Up to $47,500	$72,000
Ages 50–59 and 64+	$32,500 (incl. $8,000 catch-up)	Up to $47,500	$80,000
Ages 60–63 (SECURE 2.0)	$35,750 (incl. $11,250 catch-up)	Up to $47,500	$83,250

Note: The employer contribution is limited to 25% of W-2 wages (S corporation owners) or approximately 20% of net self-employment income after the SE tax deduction (sole proprietors and single-member LLCs). These rates determine whether you can reach the $72,000 ceiling.

Two Types of Contributions Explained

Employee Elective Deferral

You contribute this as the employee participant. The 2026 limit is $24,500. You can elect to defer any dollar amount up to this ceiling as long as you have at least that much in compensation or net SE income. Deferrals can be traditional (pre-tax) or Roth (after-tax) if your plan allows.

Employer Profit-Sharing Contribution

You contribute this as the employer. This is where the bulk of contributions above the deferral limit come from.

Sole proprietor / single-member LLC: Contribution = 20% × net self-employment income (after deducting half of SE tax). Maximum employer contribution: $47,500 for 2026.
S corporation owner: Contribution = 25% of W-2 wages paid by the S corp. Compensation is capped at $360,000.

How Much Income Is Required to Hit the Ceiling?

Sole proprietor: Approximately $255,541 in net SE income is needed for the employer contribution to reach ~$47,500 ($255,541 × 20%), which combined with the $24,500 deferral approaches the $72,000 ceiling.
S corporation owner: W-2 wages of approximately $190,000 produce a 25% employer contribution of $47,500, reaching the ceiling when combined with the $24,500 deferral.

Three Worked Examples

Example 1: Sole Proprietor, Age 42, Net SE Income $120,000

Net SE income after SE tax deduction: ~$113,065
Employer contribution (20%): ~$22,613
Employee deferral: $24,500
Total: ~$47,113

Example 2: S Corp Owner, Age 58, W-2 Wages $200,000

Employer contribution (25% of $200,000): $50,000
Employee deferral: $24,500
Age 50–59 catch-up: $8,000
Total: $82,500 — capped at $80,000 (§415(c) ceiling + catch-up)

Example 3: Sole Proprietor, Age 62, Net SE Income $300,000

Net SE income after SE tax deduction: ~$278,843
Employer contribution (20%): ~$55,769
Employee deferral: $24,500
Age 60–63 super catch-up: $11,250
Total: ~$91,519 — capped at $83,250

Contribution Deadlines

Employee elective deferral election: Must be made by December 31, 2026. For a new plan, the plan itself must also be established by December 31, 2026.
Employer profit-sharing contribution: Can be made up to the tax filing deadline, including extensions — April 15, 2027, or October 15, 2027 with an extension for sole proprietors.

Ready to optimize your tax strategy? Getting to the maximum solo 401(k) contribution requires coordinating compensation, deferral elections, and filing deadlines. Taylor, CPAI help models this for self-employed individuals throughout the year. See how Taylor, CPAI works →

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