Trade partners & ports: methodology

The figures are Official statistic as the U.S. Census Bureau publishes them in its International Trade API. Sums, totals, balances, shares, ranks and year-on-year changes are CK estimate: we calculate them, and each says so in its Sources & methods panel.

Measures

Imports: General imports: goods entering the United States for consumption or into customs warehouses, at customs value (what the goods cost abroad, not including freight and insurance to the U.S.).
Exports: Total exports: U.S. and foreign goods leaving the country, at free-alongside-ship (f.a.s.) value at the port of export.
Total trade: Imports plus exports. A direction with no reported figure counts as none; the total is unavailable only when neither direction is reported.
Balance: Exports minus imports, so a deficit is negative. Because customs and f.a.s. values are on different bases, it is an accounting difference between two Census series, not the balance of payments. A balance is shown only when both directions are reported.
Share: A partner’s or port’s total trade over the total of the scope named beside it: every partner, the partners in a region, or the ports listed. Each label says which.
Year-on-year change: The period against the same months a year earlier. It is unavailable when the earlier figure is missing, and reads “None a year earlier” when nothing was traded then. Single months, year to date, calendar years and the latest twelve months are compared with the matching earlier period.

Goods only: services trade is not in these statistics. Figures are not seasonally adjusted, so compare a month with the same month a year earlier, not with the month before.

Country attribution

Census attributes imports to the country of origin (where the goods were produced) and exports to the country of ultimate destination (where the exporter knows they are going), not to the country they were shipped from or through. Goods made in Vietnam and landed at Los Angeles after a stop in Singapore are Vietnamese imports. That is why the same partner can appear at ports far from where it borders.

Only individual countries and territories are kept, by Census’s Schedule C code. Census’s own groups (continents, the EU, “world”) are used to check our totals and are not shown as partners. Regions on the site are CK Economics’s grouping by the first digit of the code, with Mexico counted in North America.

Port coverage against national totals

Two Census series are used. The national series gives each partner’s total trade whatever the port; the port series gives each partner’s trade at each U.S. customs district or port. Port figures are the more detailed view of the national figure, not an addition to it.

Ports are listed on the site when Census names them and they are not pseudo-ports. Census codes from 6000 up are pseudo-ports (vessels under own power, low-value shipments, mail and similar) that carry real trade but are not places. Their trade counts toward coverage and is in the bulk files.
Coverage is the trade through listed ports (or through all ports) over the national total, shown on each country page. Listed-port figures add up to less than the national total, and port-level subtotals are labelled that way.
A month is published only when the ports’ world total is 95–101% of the national world total in each direction (see the release gate).

Main mode

A port’s main mode is the way its trade by value moved over the latest twelve months, both directions and every partner. It is a property of the goods, not the kind of gateway: an airport can clear trucked goods and a seaport air freight.

Vessel at least half the value: mainly vessel.
Otherwise air at least half: mainly air.
Otherwise vessel and air together under half: mainly land/other (truck, rail, pipeline and the rest).
Otherwise mixed.

Census reports vessel, air and containerised values and weights. The other modes are what vessel and air leave, never computed from subtraction, so only vessel and air shares are drawn. Containerised cargo is a part of vessel, never added to it. The label is refreshed only when all twelve months are published; a port with no trade to share out has none.

Units and periods

Values are U.S. dollars, shown as $94.3B, $612.4M or $48.2K and in full in downloads. Weights are kilograms.
Pages show 2025 onward. 2024 is collected so 2025 has a year-earlier figure.
Periods are one month, the year to date, a complete calendar year, or the latest twelve months, and are offered only when every month in them is published. Sums add monthly values.
Product detail (HS2, HS4, HS6) is queried live from Census for the period, using its year-to-date fields, and labelled as such.

Missing, suppressed and zero

Not reported: Census gave no figure, for example a vessel value left blank. It is never shown as $0, and an asterisk marks a period sum that leaves out months not reported. On a country page, a main-mode group whose ports didn’t all report a month sums the ports that did, and is marked the same way.
Unavailable: a calculation has no valid input, such as a year-on-year change with no earlier figure.
None a year earlier: the earlier period was reported and nothing was traded in it, so there is no rate of change to give.
No row: a partner or port with no trade in a published month traded nothing in it, and counts as zero in sums. Rows where every value is zero are dropped on collection.
Census suppresses some detail to protect confidential business data. We show and itemise only what Census publishes.

Revisions

Census revises months after first release and publishes an annual revision with the June release. When a new month arrives, CK Economics re-collects the previous twelve; after the annual revision it re-collects everything; and any older month whose national total no longer matches Census’s is re-collected too. A revised month replaces the earlier figures.

Each partner and port total that changed is logged with the release day. A figure appearing from, or dropping to, zero or no row is not logged as a revision. A country or port page shows “Revised on [date]” when the latest release that touched the period moved a displayed figure (imports, exports or total) by more than 1%. The full log is revisions.csv.

The release gate

A month is published only if all of these hold, and otherwise its earlier figures, if any, stay live:

It is available in all four Census series: imports and exports, port and national.
Every region’s request returned rows, in both directions.
The partners’ national totals sum to Census’s world total.
Each continent’s port sum matches Census’s own total for it, within 0.1%.
Ports sum to 95–101% of the national world total in each direction.
There are no duplicate rows.
The world total moves by no more than 30% from the previous month.

The release and retrieval dates under each chart are the day CK Economics last collected and checked the latest month shown, not Census’s own release calendar.

Comparability

Imports at customs value and exports at f.a.s. value are not the same basis, so a balance is an approximation of the trade gap.
Origin and destination attribution differ from where goods ship from, and re-exports and transshipment can move trade between partners.
Port trade is where goods cross the border, not where they are produced or consumed.
Port names and districts are Census’s and change over time; compare ports by code.
Other agencies’ and countries’ statistics (balance-of-payments, a partner’s mirror data) will not match to the dollar.
Commodity (HS) detail is queried live from Census, so it can be newer than the monthly figures CK has checked.

HS-level bulk data is not provided here; Census’s USA Trade Online has it. Bulk files of what this section shows are on the downloads page. See the Research Standards for how every figure is labelled.

How the trade figures are made