# How Many HSN Digits Must a GST Invoice Show? The 4, 6, 8 Rule

**Category:** GST | **Published:** 2026-06-26 | **Last reviewed:** 2026-06-26 | **Author:** Mrs. Swapna Patel

HSN code depth is the number of digits you must quote for each item on a GST invoice. Notification 78/2020 – Central Tax fixes the minimum by aggregate turnover: 4 digits up to ₹5 crore and 6 digits above ₹5 crore, with 8 digits required for exports, imports, and specified goods. From the January 2025 return period, the GSTN has tightened how those codes are reported in GSTR-1, so a missing or short code is now flagged at filing, not just on the invoice.

> **Myth:** A 2-digit chapter heading is enough HSN detail for any GST invoice.
>
> **Fact:** The minimum HSN depth is tied to turnover under [Notification 78/2020 – Central Tax](https://www.cbic.gov.in/htdocs-cbec/gst/cgst-notification): 4 digits up to ₹5 crore, 6 digits above it, and 8 digits for exports and certain notified goods.

## How many HSN digits does the law require?

> **Short answer:** The minimum depth follows aggregate turnover under [Notification 78/2020 – Central Tax](https://www.cbic.gov.in/htdocs-cbec/gst/cgst-notification): 4 digits up to ₹5 crore, 6 digits above ₹5 crore.

Turnover here means aggregate annual turnover in the preceding financial year. A business that crosses ₹5 crore moves up to 6 digits for every line, not only for high-value items.

| Situation | Minimum HSN digits |
| --- | --- |
| Aggregate turnover up to ₹5 crore (B2B supplies) | 4 digits |
| Aggregate turnover above ₹5 crore | 6 digits |
| Exports, imports, and certain notified goods | 8 digits |

*Minimum HSN digits required on a GST invoice*

## When do you need an 8-digit HSN code?

> **Short answer:** For exports and imports, and for specified goods such as certain chemicals and notified commodities where the government requires the full 8-digit tariff code.

- Export and import documentation runs on the 8-digit tariff line, so an export invoice should carry the full code.
- A short list of notified goods carries an 8-digit requirement even for domestic supplies; check whether your product is on it.
- When in doubt, the longer code is safer: 8 digits always contains the correct 6-digit and 4-digit code inside it.

## What changed under the 2025 HSN reporting rule?

> **Short answer:** From the January 2025 return period, the [GSTN](https://www.gst.gov.in) replaced manual HSN entry in GSTR-1 with a dropdown selection and a mandatory HSN summary table, so a wrong or absent code is caught at filing.

- HSN codes must now be picked from a validated list rather than typed, which blocks made-up codes.
- The HSN summary in GSTR-1 is split between B2B and B2C supplies and must reconcile with the invoice values.
- The phased rollout has shifted dates and slabs before, so confirm the current GSTN advisory for the period you are filing.

**[See where HSN sits among all Rule 46 invoice fields](https://hrareceipt.in/atlas/gst-tax-invoice-rule-46-field-anatomy)**

## Why does getting the digit depth wrong cost you?

> **Short answer:** Too few digits is treated as an incomplete invoice particular under [Rule 46](https://www.cbic.gov.in/htdocs-cbec/gst/cgst-rules-as-amended), and now also fails GSTR-1 validation, which can delay your buyer claiming credit.

- A short HSN code can trigger a GSTR-1 error and hold up the return until it is fixed.
- A wrong code points to the wrong tax rate, creating a mismatch the buyer must resolve before claiming input tax credit.
- Quoting the correct depth from the first invoice avoids re-issuing bills and chasing corrections later.

**[Generate a GST invoice with the right HSN field](https://hrareceipt.in/pakka-bill)**

## Primary sources

- [Notification No. 78/2020 – Central Tax — CBIC](https://www.cbic.gov.in/htdocs-cbec/gst/cgst-notification) — Number of HSN digits required on a tax invoice based on aggregate turnover, effective 1 April 2021.
- [Rule 46, Central Goods and Services Tax Rules 2017 — CBIC](https://www.cbic.gov.in/htdocs-cbec/gst/cgst-rules-as-amended) — HSN code of goods or services as a mandatory particular of a tax invoice.
- [GSTN advisory on Phase-wise HSN reporting in GSTR-1 / GSTR-1A — GST portal](https://www.gst.gov.in) — Mandatory selection of HSN from a dropdown and an HSN summary table; tightened from the January 2025 return period.

## Related

- [What is an HSN or SAC code, and why the wrong one blocks ITC](https://hrareceipt.in/answers/what-is-hsn-sac-code)
- [GST tax invoice fields under Section 31 and Rule 46](https://hrareceipt.in/answers/gst-tax-invoice-fields-section-31-rule-46)
- [What is GSTR-1, the outward supplies return](https://hrareceipt.in/answers/what-is-gstr-1-outward-supplies-return)
- [What is a pakka bill — the GST invoice that counts as valid](https://hrareceipt.in/answers/what-is-a-pakka-bill)

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*Source: [How Many HSN Digits Must a GST Invoice Show? The 4, 6, 8 Rule](https://hrareceipt.in/answers/hsn-code-digit-depth-4-6-8-rule) — HRAReceipt.in*
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