How the Solo 401(k) Contribution Calculator Works
A Solo 401(k) allows self-employed individuals to contribute in two roles — as the “employee” (elective deferral) and as the “employer” (profit-sharing contribution) — often resulting in much higher total contribution limits than a SEP IRA.
This Solo 401(k) calculator computes:
- Maximum Employee Deferral — your elective deferral limit, including any catch-up
- Maximum Employer Contribution — your profit-sharing contribution as the business
- Total Solo 401(k) Contribution — combined employee + employer amount
- Remaining Contribution Room — how much room is left versus the overall IRS limit
Solo 401(k) Contribution Formula
Employee Deferral = Deferral Limit + Catch-Up (if age-eligible)
Employer Contribution = Net Self-Employment Income × Employer Contribution %
Total Contribution = MIN(Employee Deferral + Employer Contribution, Overall Limit + Catch-Up)
Solo 401(k) Examples
Example 1: Business Owner Age 45
| Variable | Value |
|---|---|
| Net SE Income | $150,000 |
| Age | 45 |
| Employee Deferral | $23,500 |
| Employer Contribution (20%) | $30,000 |
| Total Contribution | $53,500 |
Example 2: Business Owner Age 62 (Enhanced Catch-Up)
| Variable | Value |
|---|---|
| Net SE Income | $200,000 |
| Age | 62 |
| Employee Deferral (with catch-up) | $34,750 |
| Employer Contribution (20%) | $40,000 |
| Total Contribution | $74,750 |
Who Benefits from the Solo 401(k) Contribution Calculator?
This Solo 401(k) calculator is designed for:
- Self-employed individuals with no full-time employees maximizing retirement savings
- Freelancers and consultants comparing Solo 401(k) vs. SEP IRA contribution limits
- Business owners nearing retirement using catch-up contributions to boost savings
- Financial planners modeling contribution strategies for self-employed clients
Frequently Asked Questions
What is a Solo 401(k)?
A Solo 401(k) is a retirement plan designed for self-employed individuals with no employees (other than a spouse), allowing contributions in both the “employee” and “employer” roles for higher total contribution limits.
How much can I contribute to a Solo 401(k)?
You can contribute as an employee (elective deferral, up to the annual limit plus catch-up if eligible) and as an employer (a percentage of net self-employment income), subject to an overall combined dollar limit.
What is the SECURE 2.0 enhanced catch-up contribution?
Starting in 2025, employees ages 60 to 63 may be eligible for a higher “super” catch-up contribution limit than the standard age-50 catch-up, under provisions of the SECURE 2.0 Act.
Can my spouse also contribute to my Solo 401(k)?
Yes, if your spouse works in the business and receives compensation, they can also make employee and employer contributions to the same Solo 401(k) plan, subject to their own limits.
Is my data stored anywhere?
No. All calculations run locally in your browser. No data is sent to any server.
IRS contribution limits are adjusted periodically for inflation and are subject to change. Please verify current limits before relying on these results for tax filing purposes.