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Health & RetirementFull Deduction

Solo 401(k) Contributions

Contribute as both employee and employer - up to $70,000 total for 2025.

Tax Form

Form 1040, Line 16

Estimated Savings

$5,000-70,000/year

IRS Reference

Publication 560

Income Level

Growing ($25k-$100k)Established ($100k+)

How It Works

A Solo 401(k) allows self-employed individuals with no employees to make both employee and employer contributions. For 2025, you can defer up to $23,500 as an employee, plus contribute up to 25% of net self-employment income as an employer, for a combined maximum of $70,000. Those 50+ can add catch-up contributions.

IRS Rules & Requirements

  • Employee deferral: up to $23,500 for 2025 ($23,000 for 2024)
  • Employer contribution: up to 25% of net self-employment income
  • Combined maximum: $70,000 for 2025 ($69,000 for 2024)
  • Catch-up contribution (age 50+): additional $7,500
  • Must be self-employed with no full-time employees (spouse exception)

Real Examples

Net SE income $60,000: defer $23,500 + ~$11,000 employer = $34,500 total

Net SE income $150,000: defer $23,500 + ~$27,900 employer = $51,400 total

Age 50+ with high income: up to $77,500 total contribution (2025)

Common Mistakes to Avoid

  • Missing the plan establishment deadline (December 31)
  • Confusing employee deferral deadline (Dec 31) with employer contribution deadline (tax filing)
  • Having full-time employees (disqualifies Solo 401k)
  • Exceeding contribution limits

Pro Tip

The Solo 401(k) lets you save more than a SEP IRA at lower income levels because of the employee deferral. If your net SE income is under $200,000, Solo 401(k) usually wins.

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