The amount you can contribute to a Solo 401k definitely depends on income and whether you are contributing to a 401k or 403b through another employer. There are two components to a 401k:

1. Salary deferrals - you can contribute up to $17.5k ($23k if 50 or older by 12/31 of that year) less amounts contributed as salary deferrals into other plans. The only catch is that your net self-employment income less half of the self-employment taxes must exceed the amount of your salary deferral contribution.

2. Additional Profit Sharing Plan contribution - You can also contribute up to 20% of your net self-employment income to the plan, subject to certain limitations.


So if you are under 50, and earn $100k, you could contribute as much as $37.5k or so into a Solo 401k, which is a high percentage of what you earned.

If you have a Solo 401k, don't forget to file a Form 5500 each year by 7/31 if the account is worth more than $250k.

Zip Code: 01801