Abstract: A service engine of a processor-based system determines an estimated amount of taxes due in association with a proposed transaction based on a risk tolerance value specified by a party to the transaction, such as a seller. Multiple classification code queries are generated for classifying an item that is the subject of the proposed transaction, from which a plurality of classification code candidates are determined. Each such classification code candidate is considered in determination of multiple corresponding possible tax-due amounts, and the taxes due for the proposed transaction are determined by the service engine based on a statistical calculation corresponding to the specified risk tolerance value. The service engine provides the estimated tax due amount to one or more parties to the proposed transaction.