My net profit from a freelancer job is $2656. The IRS "self-employment estimated worksheet" calculated that my SE tax is $375.27, and "Deduction worksheet" calculated that after SE tax deduction, my maximum solo 401k contribution is $2648.37 After I pay SE TAX, the net profit reduces to $2280.73. Can I really contribute more than the profit after SE tax?
If you contribute the complete amount to your 401k, you don't own taxes on it. As a result, you can claim back the taxes you already paid, in your annual tax-filing, and yes, you can put the complete amount, including the temporarily 'missing' taxes, in the 401k (assuming you have enough cash on hand).