There are several sites that can determine your census tract based on your physical address. The Federal Financial Institutions Examination Council (FFIEC) maintains one such database. Select the fifth option entitled, 'Geocoding/Mapping System' and input your address.  Alternatively, the United States Census Bureau has recently added a similar feature to their web-site.  Please bear in mind that these features are for existing addresses that have been indexed and they may not reflect new construction in an area.