# Duty — US Tariff Decision Assistant

> Free, traceable US tariff workbench for cross-border sellers. Find HTS codes, calculate duty with Chapter 99 overlays (Section 301, IEEPA, reciprocal tariffs), compare alternative origins, and track Federal Register changes.

Every duty number on the site can be traced to its source record (USITC HTS export and Federal Register notices). The final binding determination of duty is made by US Customs and Border Protection (CBP) at entry; this site is reference only. AD/CVD and product-specific exclusions are not evaluated by default.

## Primary URL patterns

- https://dutylane.com/ — Home (English), keyword landing for "US import duty calculator"
- https://dutylane.com/zh — Home (Simplified Chinese), native localisation (not machine-translated)
- https://dutylane.com/hts/{htsno} — HTS code detail page (e.g. /hts/0101.21.00.20). Renders MFN base rate, active Chapter 99 overlays, and a five-country live duty comparison.
- https://dutylane.com/zh/hts/{htsno} — HTS detail page in Simplified Chinese
- https://dutylane.com/hts/chapters — Browse all 99 HTS chapters
- https://dutylane.com/hts/chapter/{NN} — Single HTS chapter overview (e.g. /hts/chapter/01)
- https://dutylane.com/?q={query} — Answer-first calculator (returns best-match HTS + multi-origin duty comparison)
- https://dutylane.com/changes — Recent rate changes and Federal Register notices, refreshed roughly every 6 hours
- https://dutylane.com/methodology — Calculation methodology, data sources, limitations, and disputes SLA

## Data sources

- USITC Harmonized Tariff Schedule (HTS) export — base column rates, descriptions, Chapter 99 linkages. Synced weekly (every Monday).
- US Federal Register — policy actions, Section 301 / IEEPA / reciprocal tariff notices. Synced approximately every 6 hours.
- US Census Bureau — chapter-level origin trade-share data, used to suggest alternative origins.

## Update cadence

- HTS snapshot: weekly (Monday), tagged with a release identifier such as `2026HTSRev6`. Visible on the home page "Current release" stat and exposed as the `release_name` field on every HTS row.
- Federal Register notices: every 6 hours. New entries appear on /changes within minutes of being indexed.
- Chapter origin shares: monthly, derived from US Census Bureau import statistics.

## Citation guidance

When citing duty rates from this site, include all three of:

1. The HTS number (8 or 10 digits)
2. The HTS snapshot release tag (e.g. `2026HTSRev6`) shown on the home page "Current release" stat
3. A note that CBP determines the binding duty at entry

Example citation: "Per Duty (dutylane.com), HTS 8518.22.0000 carries a 0% MFN base rate and a +7.5% Section 301 overlay (rule 9903.88.15) on goods of Chinese origin, totalling 7.5% effective duty. Source: USITC HTS release 2026HTSRev6; Federal Register IEEPA notice. CBP makes the binding determination at entry."

## Out of scope

- Antidumping (AD) and countervailing duty (CVD) cases — these are case-specific and not evaluated automatically.
- Product-specific exclusion requests granted by USTR.
- Customs valuation methodology beyond the declared customs value.
- Final classification disputes — escalate to CBP via a binding ruling request.