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.
