Schedule B is the classification system used to report U.S. exports. It's maintained by the U.S. Census Bureau, Foreign Trade Division, and like the HTS, it's based on the international Harmonized System.
For the first six digits, Schedule B numbers are identical to HTSUS numbers. The final four digits differ — Schedule B has approximately 9,000 export classifications, while HTSUS has roughly 19,000 import classifications. Schedule B is generally less granular because U.S. trade policy doesn't impose detailed duty differentials on exports.
Exporters use Schedule B numbers when filing Electronic Export Information (EEI) in the Automated Export System (AES). Many filings allow either a Schedule B or HTSUS number — but some Schedule B numbers don't have direct HTSUS equivalents, so exporters need to consult the official cross-reference tables.