ACE (Automated Commercial Environment) is the U.S. Customs & Border Protection system that holds the official record of every U.S. import โ entry numbers, HTS codes, declared values, duties paid, and liquidation dates.
The calculator needs this data because it's the authoritative source of which surcharges were actually assessed and paid on each shipment. Your broker may have records, but the ACE portal is the definitive data that CBP uses when processing protest refunds.
Good news
You don't need to be an ACE expert. The next section walks you through pulling exactly the right report in about 5 minutes.