Who it is for
A self employed person or small S corporation owner checking how much room a solo plan leaves this year.
Solo 401k Calculator
Maximum Solo 401(k) contribution figures by income and entity type
Overview
What Solo 401k Calculator does
Solo 401k Calculator works out how much can go into a one participant 401(k) plan. The inputs are income, age, and the legal form of the business; the output splits the employee deferral from the employer side.
Entity type changes the arithmetic, and the app handles sole proprietorships, LLCs, and S corporations. It also reports after-tax room, which matters to anyone looking at a Mega Backdoor Roth conversion.
Limits for 2025 and 2026 are built in. The developer marks the tool as educational: it is not tax or financial advice, and the note on the listing points toward a professional before any decision is made.
What stands out
It separates employee and employer contributions and surfaces after-tax space, rather than returning one combined ceiling.
Availability
Where Solo 401k Calculator is listed
Solo 401k Calculator is listed in the ChatGPT apps directory only. Shore District Software LLC has no connector under the same domain in the Claude directory; 392 of the 3,150 products here are on both marketplaces, and this is not one of them.
ChatGPT apps are built on MCP, and the same server can back a Claude connector, so the absence is a distribution decision rather than a technical one.
ChatGPT listing
In the ChatGPT apps directory
- Developer
- Shore District Software LLC
- Filed under
- Finance
- Listed since
- June 2026
- Authentication
- Authenticates when installed
- Website
- bestsolo401k.com
- Policies published
- Privacy policy · Terms of service
- Official listing
- Open in ChatGPT
- Snapshot
- August 2026
Example prompts from the listing
- I'm 55 with an S-Corp that paid me $120k. How Much can I contribute?
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This is an independent catalogue entry compiled by Node8 from Solo 401k Calculator's public marketplace listing as it stood in August 2026. Listing facts come from the marketplaces; the comparisons against the rest of the directory and any live-endpoint measurements are Node8's. Node8 is not affiliated with Shore District Software LLC, and inclusion here is not an endorsement.
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