Solo 401(k) Calculator

Use this calculator to estimate the maximum Solo 401(k) contribution for a one-person business.

What this calculator does

The Solo 401(k) calculator estimates employee deferral, employer profit-sharing, catch-up contribution, and total maximum contribution. It uses IRS limits from the central limits file.

It uses:

• net self-employment income
• age
• employee deferral limit
• employer profit-sharing formula

Solo 401(k) Formula

Total = Employee Deferral + Employer Contribution + Catch-Up

Where:

• Employee Deferral = limited annual deferral amount
• Employer Contribution = net income × 92.35% × 20%
• Catch-Up = extra amount if age 50 or older
• Total = capped by IRS total limit

Example calculation

If:

• Net income = 150,000
• Employee deferral = 23,500
• Employer contribution = 27,705
• Catch-up = 7,500

Then:

• Total before cap = 58,705
• IRS total cap is checked
• Maximum contribution = 58,705
• The full cap is not reached

The Solo 401(k) maximum is 58,705.

What is a Solo 401(k)?

A Solo 401(k) is a retirement plan for a self-employed person with no employees other than a spouse. It allows both employee and employer-style contributions.

Why Solo 401(k) planning matters

• can allow high contribution capacity
• separates deferral and profit-sharing
• supports self-employed tax planning
• helps compare SEP IRA alternatives

When to use this calculator

• estimating maximum contribution
• planning self-employed retirement saving
• checking catch-up eligibility
• comparing Solo 401(k) and SEP IRA

Common mistakes

• using gross revenue instead of net income
• forgetting the employer formula
• missing catch-up eligibility
• exceeding IRS total limits

Solo 401(k) vs SEP IRA

Solo 401(k) can include employee deferral and employer contribution. SEP IRA generally uses employer contribution only.

Solo 401(k) can be more powerful at moderate income levels.

FAQs

What is a Solo 401(k)?

A Solo 401(k) is a retirement plan for a self-employed business owner with no common-law employees.

How do you calculate Solo 401(k) contribution?

Add employee deferral, employer profit-sharing, and catch-up if eligible, then apply IRS caps.

What is a good Solo 401(k) contribution?

A good contribution maximizes tax-advantaged savings without exceeding income or IRS limits.

What is the difference between Solo 401(k) and SEP IRA?

Solo 401(k) has employee and employer parts. SEP IRA is employer-funded.