Methodology
How we source and check our numbers
Updated · By Joshua Giles, founder of Supercargo (JG Core Ltd)
Where do Supercargo's numbers come from?
Every duty rate, deadline and statistic on this site is read from a primary source: the US Harmonized Tariff Schedule, CBP’s own pages and CSMS messages, the Federal Register, or the importer’s own filed entries. Each figure is shown with its source and the date we last checked it, and nothing is estimated or copied from secondary sites.
Tariff code pages
- Each HTS page lists every layer of duty separately: the general rate, then each Chapter 99 line, each with the source it was read from.
- The page shows the date the figures were verified. Codes we could only partly confirm carry a visible banner that says what is unconfirmed.
- Before publishing, a check script confirms that every layer has a source and that each total equals the sum of its layers.
- We re-verify when a tariff regime changes, and move the verified date only when we have actually re-read the sources.
Guides and the IEEPA refund pages
- Each guide names the primary page it was checked against and the date of that check, for example CBP’s IEEPA Duty Refunds page and its “last modified” date.
- The “Updated” date under each heading changes only when the page’s content changes, never because the site was redeployed.
Calculators and the audit
- The landed cost calculator works from published rates and says what a published rate leaves out. It is a planning aid, not a duty determination.
- The audit works backwards from entries you have already filed, using your own ES-003 export, and reconciles what was declared and paid to landed cost per unit.
What we do not publish
For United States shipments: Supercargo is not a licensed customs broker and does not conduct customs business as defined in 19 CFR 111.1. Figures shown for prospective shipments are management estimates on a commodity code you supply. Classification, valuation and entry remain the responsibility of you as importer of record and of your licensed broker, and reliance on Supercargo does not establish reasonable care for the purposes of 19 U.S.C. 1484.
We do not give a forward duty figure for a shipment you are about to import, propose a commodity code, or prepare or file anything with CBP. Where our output and your licensed customs broker disagree, your broker is right.
Corrections
If you find a figure that does not match its source, write to hello@getsupercargo.com. We fix it, move the page’s updated date, and say what changed.
Start with the audit
Your last twelve months of entries, reconciled to the unit, for a fixed £900$1,200€1,050. Credited in full against your first year, and refunded in full if the variance is under 2%.