How Many HSN Digits Do You Need on a GST Invoice? 4, 6 or 8 Explained
HSN codes cause more confusion than almost any other field on a GST invoice. Do you need four digits or six? What about eight? Is SAC different? And what happens if you leave it out on a small B2C bill?
The answer depends mainly on your turnover and on who you are selling to. This guide sets out the rule, explains how the codes are structured, and suggests a practical way to find the right code for your products.
What HSN and SAC are
- HSN (Harmonised System of Nomenclature) is an international system for classifying goods, maintained by the World Customs Organization. India uses it, with extra digits of its own, for customs and GST.
- SAC (Services Accounting Code) is India's classification for services under GST. SAC codes start with 99.
On a GST invoice, you put the HSN code for each line of goods and the SAC for each line of services. The code tells the tax system what you are selling, which links the item to its GST rate.
How the digits are structured
| Digits | Level | Example |
|---|---|---|
| 2 | Chapter | 61: Knitted or crocheted apparel |
| 4 | Heading | 6109: T-shirts, singlets and vests, knitted |
| 6 | Sub-heading (international) | 610910: Of cotton |
| 8 | Tariff item (India-specific) | 61091000: used in the customs tariff |
The first six digits are the same in every country that uses the Harmonised System. The last two are India's own and are used mostly in customs.
The rule: digits by turnover
Notification No. 78/2020-Central Tax, effective from 1 April 2021, sets the minimum number of digits based on your aggregate annual turnover (AATO) in the previous financial year:
| AATO in previous year | Minimum HSN/SAC digits on invoice |
|---|---|
| Up to 5 crore | 4 digits on B2B invoices (optional on B2C) |
| Above 5 crore | 6 digits on all tax invoices |
So a small business with 80 lakh turnover selling to a registered buyer must show at least a 4-digit code. When selling to a consumer, it may leave the code off, though including it does no harm. A business with 12 crore turnover must show 6 digits on every invoice, B2B or B2C.
You can always show more digits than the minimum. Many businesses use 8 digits everywhere simply because their accounting software or supplier's invoices use them.
Does the same apply to services?
Yes. SAC codes follow the same digit thresholds. In practice most SAC codes are six digits long, such as 998314 for IT design and development services, or 998361 for advertising services.
HSN in GSTR-1
The HSN rules also apply to the HSN-wise summary in Table 12 of GSTR-1, where you report quantity, value and tax by HSN code. In recent years the portal has tightened this table, with codes picked from a list and B2B and B2C supplies reported separately. If your invoices use consistent codes, this table is easy to fill; if every invoice uses a different code for the same item, it becomes a headache.
Exports and imports
For exports and imports, customs requires the full 8-digit tariff code on shipping bills and bills of entry. If you export, it makes sense to use the 8-digit code on your invoices as well, so that all your documents match.
How to find the right code
- Start with your supplier's invoice. If you trade goods, the manufacturer or wholesaler has usually classified them already.
- Use the search on the GST portal. The "Search HSN/SAC" option on the public GST portal lets you search by keyword or code.
- Check the customs tariff for the full chapter notes. Classification depends on what the product is made of and how it is used, and the chapter notes settle close cases.
- Ask your CA when a product could fit more than one heading. The rate can differ, so the classification matters.
Be careful with lists of "HSN codes with GST rates" found online. GST rates have been revised many times, including the major rate rationalisation in 2025, so older lists can show wrong rates. Always confirm the current rate from official notifications.
Common mistakes
- Using a 2-digit chapter code, which is never enough.
- Using a different code for the same product on different invoices.
- Using an HSN code for a service or a SAC for goods. Repair services are SAC, even though they involve goods.
- Not updating digits when turnover crosses 5 crore. The test applies to the previous year's turnover, so check every April.
Adding HSN codes in OwnInvoice
OwnInvoice's GST invoice editor, available with a free account, has an HSN/SAC field on every line, with a search to help you find the heading. You enter the GST rate yourself, and the editor remembers it for that code next time. In the free Invoice Studio and the bill of supply generator, add the code to each item's description and use the same code for the same product every time.
Note: This article explains the digit requirements for general information. It does not classify specific products. Classification and rates should be confirmed with official sources or a tax professional.