Income Qualification For SD 401k

[Mike T.]

If you open a side business to start a SD 401k. Are you allowed to contribute gross or net income towards your 17,500 contribution?

I started one this year and only earned about 10,000. I have around 5000 in expenses. Can i contribute the full 10000 or will it be 10,000 minus expenses and taxes. I know I need an accountant but have not found one I feel is a top performer.

Thanks