For FAFSA purposes, your custodial parent information is all that will be required (you will need to include any spousal or child support received). But except for University of Chicago, the colleges that use only the FAFSA will require additional financial information usually via the CSS Profile, but sometimes with their own forms. Some of these include non-custodial parent and spouse information.
If a net price calculator specifically asks for marital status, and asks for non-custodial parent info If the college requires it…then it might be a decent estimate of your net cost.
BUT many NPCs don’t ask for marital status of parents or non-custodial parent income and assets. If a school requires the Profile, and requires the non-custodial parent Profile, then info from both bio parents…and any spouses will be required. Just FYI.