to calculate use schedule A of form 1045. read the instructions because business income and losses get entered on certain lines while nonbusiness income and deductions get entered on other lines. the short version. your NOL is the excess of business losses over business income reduced by the excess, if any, of nonbusiness income over nonbusiness deductions.
https://www.irs.gov/site-index-search?search=1045&field_pup_historical_1=1&field_pup_historical=1
