If I open a SEP ira, and am self employed as a sole proprietor, how can I make contributions as the “employer” so they are business expenses and reduce SE tax?

[austinvoss123]

I am trying to reduce SE tax by putting into an IRA. Am sole proprietor. Have not found simple way to do this.

[fanfare]

You can't. Your SEP contribution has to be calculated after your tax return is complete in all other respects.

[dmertz]

A SEP contribution by a sole proprietor is not a business expense, it's an individual above-the-line deduction.  As fanfare said, it cannot be used to reduce self-employment taxes.  It only reduces AGI.  Only SEP contributions for your employees (other than yourself) are a business expense that is deductible on Schedule C.