HSN Code and Customs Tariff Heading (CTH)

What Is an HSN Code and Customs Tariff Heading (CTH)?

The HSN Code (Harmonised System of Nomenclature) is the numeric code that classifies a product for tax and customs purposes in India, and the Customs Tariff Heading (CTH) is the same code as it appears in the First Schedule to the Customs Tariff Act, 1975 — the statutory tariff schedule that fixes the rate of customs duty on every imported or exported good. In practice "HSN code" and "CTH" refer to the same classification system: goods and services suppliers use the term HSN Code on GST invoices and returns, while importers and exporters use CTH on the Bill of Entry and Shipping Bill filed through ICEGATE, India's national customs gateway. The code is built in a fixed hierarchy — 2 digits for the Chapter, 4 digits for the Heading, 6 digits for the Sub-heading, and (for customs purposes) 8 digits for the Tariff Item — so an 8-digit CTH tells a customs officer, in that order, which chapter, which heading within it, which sub-heading, and which specific national tariff line the goods fall under.

For a foreign company setting up in India, the HSN/CTH is not paperwork trivia. It is the single field that determines the customs duty rate, the GST rate, whether an import licence or a Participating Government Agency (PGA) no-objection certificate is needed, and whether a Free Trade Agreement preferential rate can be claimed. Get the code wrong and the shipment can be held at port, assessed at the wrong duty, or flagged for a compliance query — all before the underlying business issue is even discussed.

How the Code Is Structured

India uses the World Customs Organization's Harmonized System as the base of its tariff, then extends it for domestic use:

• Chapter (2 digits) — the broadest classification, e.g. Chapter 84 covers nuclear reactors, boilers, machinery and mechanical appliances.
• Heading (4 digits) — a category within the chapter.
• Sub-heading (6 digits) — the internationally harmonised 6-digit code, identical across WCO member countries. This is the level at which most countries' tariffs are directly comparable.
• Tariff Item (8 digits) — India's own national extension of the 6-digit sub-heading, used in the First Schedule to the Customs Tariff Act, 1975 to fix the exact rate of customs duty applicable to that specific product.

The 8-digit tariff item is the operative unit for duty. Rates and duty concessions are fixed against a specific tariff item in, or in a notification issued under, the First Schedule to the Customs Tariff Act, 1975, so two products sharing the same first six digits can still be assessed differently.

HSN Codes Under GST — the Digit Requirement by Turnover

Separately from the customs tariff, GST law requires suppliers to quote an HSN code on tax invoices, based on their turnover in the preceding financial year. The governing instrument is Notification No. 78/2020 – Central Tax, dated 15 October 2020. In the GST Network's own words, that notification makes it "mandatory for the taxpayers to report minimum 4 digits or 6 digits of HSN Code in Table-12 of GSTR-1 on the basis of their Aggregate Annual Turnover (AATO) in the preceding Financial Year":

The same digit split governs the HSN summary a taxpayer reports in the GSTR-1 return (Table 12), where the GST Network validates the HSN entered against the taxpayer's turnover band. The GST portal has implemented this in phases, moving from free-text entry with a warning message towards validated codes, so an HSN that a return accepted in an earlier period may be refused in a later one.

Read the 4 and 6 digit figures as a floor rather than a ceiling. The notification fixes the minimum number of digits a supplier must show, so quoting the fuller 8-digit tariff item does not breach it. The 8-digit tariff item stays the unit customs works in, on the Bill of Entry and the Shipping Bill.

Where CTH Is Used in Customs Clearance

Every import or export shipment into or out of India must be declared to a specific CTH. The importer's customs broker or in-house team enters the CTH on the Bill of Entry (for imports) or Shipping Bill (for exports), filed electronically through ICEGATE. The declared CTH drives several downstream outcomes at the same time:

• Duty rate. Basic Customs Duty, IGST, and any Social Welfare Surcharge are all keyed to the CTH under the First Schedule to the Customs Tariff Act, 1975 and the notifications issued under it.
• Licensing and NOC requirements. Certain CTHs trigger a requirement for a Participating Government Agency (PGA) no-objection certificate — for example, from the Food Safety and Standards Authority of India, the Drug Controller, or the Bureau of Indian Standards — before customs clears the goods. ICEGATE's Single Window Interface for Facilitating Trade (SWIFT) routes these NOC requests to the relevant PGA based on the declared CTH.
• Import policy status. The Directorate General of Foreign Trade's ITC(HS) classification — itself built on the same 8-digit structure — marks specific CTHs as "free," "restricted," or "prohibited" for import or export, so the CTH also determines whether a licence from DGFT is needed at all.
• Preferential tariff eligibility. Claiming a reduced duty rate under an FTA requires the CTH declared on the Bill of Entry to match the CTH certified on the exporter's Certificate of Origin.

ICEGATE also hosts the Compliance Information Portal (CIP), described on its own site as a "portal for customs procedures, compliance, agency links, tariffs, and duties for each commodity" — a lookup tool built around CTH codes that importers and their brokers use before filing, to confirm duty rates and any licence or NOC condition attached to a given classification.

Why This Matters for a Foreign Company or Investor

Foreign companies setting up manufacturing, trading, or import-dependent operations in India encounter HSN/CTH at three points:

1. Product costing. The landed cost of an imported machine, component, or raw material is directly a function of its CTH-linked duty rate. Two products that look similar to a non-specialist can sit in different sub-headings with materially different duty rates.
2. GST compliance from day one. Any invoice issued by an Indian subsidiary — whether for a domestic sale or an export — needs the correct HSN code at the digit-count required for its turnover band, from its very first invoice.
3. Import licensing risk. A foreign company importing capital equipment or inputs for its Indian operations needs to confirm, before the goods ship, that the intended CTH is not marked "restricted" or "prohibited" under the DGFT's import policy — otherwise the shipment cannot clear customs without an import licence obtained in advance.

Misclassification is not a paperwork formality either way. Declaring the wrong CTH — even unintentionally — can result in customs reassessing the shipment at a higher duty rate, demanding the duty differential, and in more serious cases opening penalty or confiscation proceedings under the Customs Act, 1962. Getting the classification confirmed before the first shipment, rather than after a customs query, is the cheaper path.

Worked Example

A US-based industrial equipment company sets up an Indian subsidiary to assemble and sell control panels. It imports a batch of programmable logic controllers (PLCs) for the assembly line.

• The customs broker identifies the heading that covers the PLCs, then confirms the correct 8-digit tariff item within that heading based on the product's specific function, since tariff items under a single heading can carry different duty treatment.
• The Bill of Entry is filed via ICEGATE with that CTH, and the assessed Basic Customs Duty and IGST are calculated using the rate applicable to that tariff item under the First Schedule.
• Because the subsidiary's turnover in its first year is below Rs 5 crore, its GST invoices for the finished control panels need a minimum of 4 HSN digits, rising to a minimum of 6 once turnover crosses Rs 5 crore, under Notification No. 78/2020 – Central Tax.
• If the subsidiary later imports components from a country with which India has an FTA, it checks that the CTH used for the Certificate of Origin matches the CTH declared on the Bill of Entry before claiming the preferential rate.

Frequently Asked Questions

Is an HSN code the same as a Customs Tariff Heading (CTH)?

Yes, for practical purposes they are the same numeric classification. "HSN code" is the term used in GST invoicing and returns, while "CTH" is the term used for the identical code on customs documents such as the Bill of Entry and Shipping Bill, where it is drawn from the First Schedule to the Customs Tariff Act, 1975.

How many digits does my GST invoice need?

Under Notification No. 78/2020 – Central Tax, a supplier with turnover up to Rs 5 crore in the preceding financial year must report at least 4 HSN digits, and a supplier above Rs 5 crore at least 6. Those are minimums, not fixed lengths. Customs declarations work in the fuller 8-digit tariff item.

Who decides which CTH applies to my product?

Classification follows the General Rules for Interpretation of the Harmonized System, applied to the specific product's description, composition, and use, against the First Schedule to the Customs Tariff Act, 1975. In practice, a customs broker or classification specialist determines the CTH before the Bill of Entry is filed. An advance ruling can be sought to settle the classification in advance, and customs can reassess a declared classification during clearance.

What happens if the wrong CTH is declared?

Customs can reassess the shipment under the correct classification, demand any duty shortfall, and — depending on the facts — pursue penalty or confiscation proceedings under the Customs Act, 1962. An incorrect CTH can also mean a required import licence or PGA no-objection certificate was missed, which can hold the shipment at port.

Does the CTH affect whether I can import a product at all?

Yes. The Directorate General of Foreign Trade classifies CTHs as "free," "restricted," or "prohibited" for import or export under the ITC(HS). A restricted classification means an import licence from DGFT is needed before the goods can clear customs; a prohibited classification generally bars the import outright.

See also: Customs Documentation: Bill of Entry & Shipping Bill, Custom Duty & Anti-Dumping Duty, and Free Trade Agreement (FTA) & Rules of Origin.

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