Solo 401(k) Contribution Calculator
Calculate maximum Solo 401(k) / Individual 401(k) contribution limits for self-employed professionals and small business owners. Model employee elective deferrals, 25% employer profit-sharing, and total tax savings.
Includes $23,000 employee deferral + $35,000 employer profit sharing.
Business & Income Parameters
Maximizing Retirement Wealth with a Solo 401(k)
For self-employed consultants, freelancers, and small business owners with no full-time W-2 employees (other than a spouse), the Solo 401(k) is the most powerful retirement vehicle in the Internal Revenue Code. It allows business owners to contribute in two distinct capacities: as an employee (up to $23,000, plus $7,500 catch-up for age 50+) and as an employer (up to 25% of compensation or 20% of net self-employment earnings), up to an overall limit of $69,000 ($76,500 for 50+).
High-Net-Worth Features
Dual Employee & Employer Contribution Engine
Accurately calculates employee elective deferrals ($23,000 / $30,500) and employer profit-sharing (up to 25% of W-2 or 20% of Schedule C net earnings).
Entity-Specific Compensation Math
Tailored calculations for S-Corporations (W-2 salary basis) and Sole Proprietorships / Single-Member LLCs (Schedule C net profit less self-employment tax deduction).
Age 50+ Catch-Up Integration
Automatically applies the additional $7,500 catch-up contribution threshold for business owners aged 50 and older.
Marginal Tax Bracket Savings
Estimates immediate federal and state income tax savings resulting from pre-tax Traditional Solo 401(k) deductions.
Traditional vs. Roth Solo 401(k) Allocation
Model splitting contributions between pre-tax tax deductions and post-tax Roth compounding.
IRS Section 415(c) Limit Safeguards
Enforces strict adherence to statutory annual additions caps ($69,000 in 2024 / $70,000+).
Tax & Financial Planning Scenarios
- ✓S-Corporation Owner-Employees
Optimize W-2 shareholder salary vs distribution splits to maximize corporate profit-sharing deductions.
- ✓High-Income 1099 Consultants & Freelancers
Shelter up to $69,000+ from top federal tax brackets (32%, 35%, 37%) using Schedule C earnings.
- ✓Spousal Business Partnerships
Double annual household retirement contributions up to $138,000+ by employing a spouse in the business.
- ✓Mega-Backdoor Roth IRA Planners
Determine after-tax space available for in-plan Roth rollovers within self-directed trust prototypes.
Frequently Asked Questions
Who is eligible to open a Solo 401(k)?
To qualify for a Solo 401(k), you must have self-employment business activity (sole proprietorship, LLC, S-Corp, C-Corp, or partnership) and have no full-time common-law W-2 employees other than yourself and your spouse. Part-time employees working under 1,000 hours per year (or 500 hours over 3 consecutive years under SECURE 2.0) are generally excluded.
What is the difference between S-Corp and Sole Proprietor Solo 401(k) calculations?
For an S-Corporation, contributions are based solely on your W-2 wage: employee deferrals up to $23,000 plus employer profit-sharing up to 25% of W-2 pay. For a Sole Proprietor or Single-Member LLC filing Schedule C, profit-sharing is calculated at 20% of net self-employment earnings after subtracting one-half of your self-employment tax.
Can I contribute to both an employer 401(k) and a Solo 401(k) in the same year?
Yes, but the employee elective deferral limit ($23,000 across all 401k plans) is per person, not per plan. However, the employer profit-sharing contribution (up to the overall $69,000 limit) is separate for your own business, allowing you to contribute substantial employer funds to your Solo 401(k) even if you maxed out employee deferrals at your day job.
Can my spouse contribute to my Solo 401(k)?
Yes. If your spouse earns legitimate W-2 wages or self-employment compensation from your business, they can make their own full employee contribution ($23,000) and receive employer profit-sharing, effectively doubling your household tax shelter.
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