2024 Solo Roth IRA - getting 2 different numbers I don't understand

[caginaz1]

On the individual and Roth 401k plans tab, I input Roth 401k info of 23,000 elective and catchup of 7,500 (I'm over 59 1/2) for the total of 30,500.  My co made $34,754 Net income.  I checked the box to maximize contrib to individual 401K.  On the self-employed retirement deduction page, it says I can defer a max of $27,649. Then on the Your Retirement Contributions page, it indicates I can my maximum allowed to qualified plans is $1,798, which I would assume would be into the employer match?  But as this is a Roth account, is that limit correct or can I go up to the total of my net earnings, and add $4254 instead (I live off of other retirement income/SS, no w2 work, no other 401k)?  And I'd want to do it as a Roth Employer match?  

Thanks!

[AmyC]

The IRS limits contributions to plan specifications or 100% of the employee's compensation, whichever is less.

Reference: Retirement contributions  limit

Your income changes when you deduct the amounts into the plan. If you have $30k income and then pay $30k into plan, it is subtracted from your income, then you have no income. You have to find the sweet spot for you to have income and deduct the business contributions.

[dmertz]

Your contributions are limited to net earnings from self employment.  Net earnings are net profit minus the deductible portion of self-employment taxes.  On $34,754 of net profit, the deductible portion of SE taxes is $2,456, leaving $32,298 as the amount of your net earnings.  After making $30,500 in employee Roth 401(k) contributions, that leaves only $1,798 available to make the employer contribution.