The U.S. tariff schedule's three rate columns, measured (HTS Revision 18, 2026) Aervik Labs (operated by EAC Ventures, LLC) https://aerviklabs.com/research/hts-rate-columns-2026-rev18/ LICENSE CC BY 4.0 -- https://creativecommons.org/licenses/by/4.0/ Free to use and redistribute, including commercially, with attribution. SUGGESTED CITATION Aervik Labs. "The U.S. tariff schedule's three rate columns, measured (HTS Revision 18, 2026)." Measurement of the U.S. International Trade Commission's Harmonized Tariff Schedule export, release 2026HTSRev18, pulled 2026-09-15. https://aerviklabs.com/research/hts-rate-columns-2026-rev18/ (CC BY 4.0) WHAT THIS IS Counts of the three rate columns in the U.S. Harmonized Tariff Schedule as USITC's export prints them: General and Special (the two subcolumns of column 1) and Column 2. Release 2026HTSRev18 ("Revision 18 (2026)", dated 2026-08-27, in effect from 2026-09-02, status "current" when pulled on 2026-09-15 between 2026-09-15T02:49Z and 2026-09-15T02:50Z). Scope: chapters 01-97. Chapters 98 and 99 are summarized apart in summary.json and are in no headline figure. Headline figures (8-digit rate lines, chapters 01-97): - 11,414 lines; 19,926 most-detailed rows. - Every one of the 7,099 lines whose General rate is not Free carries Special text, and every one of those texts lists at least one program at Free. 6,722 list only Free rates. No line whose General rate is Free carries Special text. - General: Free 4,315 (37.8%), ad valorem 5,863 (51.4%), specific 759, compound 397, other 80. - Column 2: every line carries a rate. Where General and Column 2 are both ad valorem (5,264 lines), Column 2 is higher on 5,228 and equal on 36; reading Free as 0% (8,804 comparable lines), no line has Column 2 below General. Specific, compound and other forms are counted, not compared. - The duty-free share depends on the unit counted: 37.8% of 8-digit lines, 36.9% of most-detailed rows, and 39.0% to 52.8% of 5,612 HS six-digit subheadings depending on how a subheading with mixed lines is counted. WTO's "Share of MFN duty-free" (2025) is 47.5%, counted over HS six-digit subheadings by WTO's own method; it is a different unit and year, and nothing here corrects it. Program symbols and names are General Note 3(c)(i) of the same revision; the Column 2 countries are General Note 3(b) of the same revision: Republic of Belarus, Cuba, North Korea, Russian Federation. The counts are what the schedule prints. Whether a program is in effect, and which countries and goods qualify, is set by statute and presidential proclamation outside the schedule; nothing here says whether any program currently applies. Subjects: Tariff schedule lines and rate texts. No person, company or shipment is named or counted. UNITS 8-digit rate line a distinct first eight digits among numbered 8- and 10-digit rows. An 8-digit row and its 10-digit statistical suffix rows are one line. most-detailed row every 10-digit row, plus every 8-digit row with no 10-digit row under it. Rows under one 8-digit line carry the same rate texts (checked on every line); a row with a blank General takes its line's texts. A blank General is never read as Free. RATE FORMS (after collapsing whitespace) Free the text "Free" ad valorem a number and "%", or a whole number and a fraction before "%" specific one money amount per unit, optionally qualified compound parts joined by "+", at least one specific amount and at least one percentage other anything else: references ("The rate applicable to ..."), formulas, percentages on a stated basis, several specific amounts. Every "other" General text is listed in summary.json (general.lines.other_texts). FILES special-by-symbol.csv One row per program symbol General Note 3(c)(i) lists (29 rows), in the note's order. symbol the symbol as the schedule prints it program the program's name in General Note 3(c)(i) program_symbols_as_printed every symbol of that program, as the note prints them lines_listing 8-digit lines whose Special text lists the symbol lines_free of those, lines where the symbol's listed rate is Free lines_stated_rate_not_free lines where it is a stated rate other than Free lines_reference lines where it is a reference instead of a rate, almost always a pointer to a chapter 98 or 99 provision ("See 9823.04.01-9823.04.54 (S+)") lines_ad_valorem_below_general lines where it is a percentage below the General rate lines_ad_valorem_equal_to_general lines where it is a percentage equal to the General rate most_detailed_rows_* the same counts per most-detailed row A line lists a symbol once even if the text prints it twice at the same rate. Symbols the note does not list are not in this file (see summary.json, as_printed). by-chapter.csv One row per chapter 01-97 present in the schedule (96 rows; chapter 77 is reserved). Unit: 8-digit lines. lines 8-digit lines in the chapter general_free, general_ad_valorem, general_specific, general_compound, general_other lines by General rate form with_special_text lines with any Special text col2_vs_general_comparable lines where General and Column 2 are each Free or ad valorem, with Free read as 0% col2_vs_general_higher, _equal, _lower of those, Column 2 higher than, equal to, below General summary.json Every figure on the page: release and sources with read times, units, the General, Special and Column 2 counts in both units, per-symbol and per-program counts, the duty-free share by unit beside WTO's figure and method, what the schedule prints as printed (symbols not in the note, rates equal to General with no suspended marker, the additionalDuties field), chapters 98-99, the checks and the request counts. License and citation. README.txt This file. METHOD Source: USITC's keyless export, https://hts.usitc.gov/reststop/exportList?from=...&to=...&format=JSON|CSV&styles=false. The export carries no revision field, so the release was read from https://hts.usitc.gov/reststop/currentRelease before (2026-09-15T02:49Z) and after (2026-09-15T02:50Z) the pull and matched, and from https://hts.usitc.gov/reststop/releaseList. The schedule was pulled twice, in JSON (14 chunks) and in CSV (13 chunks) with different chunk boundaries; consecutive chunks had to overlap row for row, and the two pulls (35,804 records each) matched record for record on HTS number, indent, description, General, Special and Column 2 once leading and trailing whitespace was trimmed. General Note 3: https://hts.usitc.gov/reststop/file?release=2026HTSRev18&filename=General%20Note%203 (fetched 2026-09-15T02:50Z, 45,465 bytes, SHA-256 7e6438e2025fc6b10ce18c2dbf15c2bad3e0a02b46ed7b00d5a7f0f1d1d62c58, running header "Revision 18 (2026)"), decoded two independent ways with identical text. Computed two ways, each stopping on disagreement: 8-digit lines (distinct prefixes and rows carrying a General rate); most-detailed rows (suffix set and leaf walk); every row's rate texts (8-digit prefix and indent walk); every rate form (two classifiers); every Special text (two parsers); General Note 3 (two decodings). 76 fixture checks on the classifiers and parsers, 0 failed; 4 copies of the data broken on purpose each stopped the measurement with the reason it exists to catch. The Landed Cost API's bundled schedule snapshot dated 2026-09-14 matches this pull code for code: 11,414 lines, 23,193 rows, the same General text on every line. LOAD 116 logged requests (104 to hts.usitc.gov, 12 to ttd.wto.org), every one answered HTTP 200, including stopped and superseded runs. One request at a time; the smallest gap between two request starts was 3,498 ms. User-Agent: AervikLabs-research/1.0 (tariff schedule rate-column measurement; https://aerviklabs.com). hts.usitc.gov/robots.txt answered the site's HTML page (text/html; charset=UTF-8), with no directives; ttd.wto.org/robots.txt has an empty Disallow for every agent. Two earlier runs, of the probe step and of the WTO read, made the same requests as their logged runs and are not in these counts. The World Tariff Profiles PDF was read separately and is not in them. LIMITATIONS - One revision, pulled on one day. Counts change with every USITC revision. - Unweighted: a line counts once, whatever is imported under it. No trade values. - Rates as printed. No ad valorem equivalents are estimated; specific and compound rates are counted, not converted. - Text, not law. A program listed at Free says what the schedule prints for goods that meet that program's requirements; it says nothing about which goods or countries qualify, rules of origin, quotas, or whether a program or designation is in effect. - Chapters 98 and 99 are out of every headline, so nothing here reflects Section 301, Section 232, IEEPA or other additional duties, temporary suspensions, or the provisions Special references point to. - No statement about the duty on any product or shipment. - The rate-form patterns are this study's definitions; the shapes outside them are listed verbatim. - The gap between WTO's figure and any of these shares is not explained here. Not legal or customs advice.