HSN Code on GST Bills: 4, 6 or 8 Digits? A Simple Guide for Shop Owners

Ask a shop owner for the HSN code of something they sell every day, and many will say, “CA ko pata hoga.” A customer wants a GST bill for cement, your accountant asks for the 6-digit code, and a website shows you 8 digits. Which one goes on the bill?

The answer depends on three things: your turnover, who you are selling to, and whether you export. Here is how it works, with cement as the example, and what to clean up in your item list this month.

What the digits mean

HSN stands for Harmonized System of Nomenclature. It is a numbering system for goods. Each extra pair of digits makes the description more exact. Here is how one cement code breaks down:

• 25 is the chapter, which covers salt, stone, lime and cement.
• 2523 is the heading: Portland, aluminous, slag and similar cements.
• 252329 is the sub-heading for other Portland cements, including OPC, PPC and slag cement.
• 25232930 is the exact item: Portland pozzolana cement (PPC).

So all four are “the code for PPC cement”. The difference is how much detail you show. Services use SAC codes in the same way, and these begin with 99.

How many digits your bill must show

The rule comes from Notification No. 78/2020 – Central Tax, in force since 1 April 2021. It looks at your aggregate turnover in the previous financial year.

Your situation	Digits on the invoice
Turnover up to ₹5 crore, selling to a GST-registered buyer (B2B)	4 digits required
Turnover up to ₹5 crore, selling to an ordinary customer (B2C)	Optional
Turnover above ₹5 crore, B2B or B2C	6 digits required
Exports	8 digits

One detail catches people out: turnover is counted across your PAN, not per GSTIN. Taxguru gives the example of a business with five GSTINs doing ₹2 crore each. Each looks small, but together they cross ₹5 crore, so 6 digits apply to all of them.

Worked example: a hardware shop selling cement

Say your shop did ₹1.8 crore last year and you sell PPC cement.

• Bill to a contractor with a GSTIN: show at least 2523.
• Bill to a homeowner without a GSTIN: the code is optional, though keeping it on the bill does no harm.
• Next year, turnover crosses ₹5 crore: from the following financial year, show 252329 on every bill.

Check the rate at the same time. The GST rate on cement fell from 28% to 18% from 22 September 2025, as reported by Global Cement. Older lists and articles can still show the old rate. Always confirm rates against the latest CBIC notification or with your CA, because the code and the rate are two separate things to verify.

Your invoice and GSTR-1 are linked

The digits on the bill are only half of it. Table 12 of GSTR-1 reports your sales summarised by HSN, and it has changed in recent years:

• Separate tabs. From the May 2025 return period, Table 12 has separate “B2B Supplies” and “B2C Supplies” tabs (Taxscan).
• Dropdown, not typing. Codes are picked from a portal dropdown instead of being typed by hand (Taxscan). If your item list has a code that does not exist, you will find out at filing time.
• Values are compared. Table 12 amounts are checked against the other tables in your return. Reports from 2025 describe these checks as warning-only, so you could still file. Taxscan said enforcement was expected to tighten in phases, so check what the portal shows you today.
• B2B cannot be blank. If you report B2B sales in other tables, the B2B tab of Table 12 cannot be left empty (abcaus).

Even if the code is optional on your B2C bills, ask your CA how they want those sales shown in Table 12.

A one-hour clean-up for your item list

Do this on a quiet afternoon, now that the Diwali rush is over.

1. Export or list your top 50 items. Start with what you sell most, by value.
2. Find the blanks. Mark items with no code, or with a code that looks copied from a neighbouring item.
3. Check your turnover. Look at last year’s aggregate turnover across your PAN, and decide on 4 or 6 digits as your minimum.
4. Look up each code. Search by item name, read the description, and make sure it matches what you actually sell. OPC and PPC, for example, have different 8-digit codes.
5. Check purchase bills. Your supplier’s invoice is a useful clue, but suppliers make mistakes too.
6. Confirm the GST rate separately. Ask your CA about anything unclear, especially mixed or unusual items.
7. Repeat for the next 50 items until the whole list is done.

Common mistakes to avoid

• One code for a whole category. “Paint and hardware” under a single code will not match what you actually sold.
• Trusting old lists. Rates and sometimes codes change, so check the date on what you are reading.
• Leaving it all for filing day. Fixing codes during filing means rushed guesses. Fixing them in your item list means every future bill is right.

How WoveOS helps

WoveOS is an AI-first business app for Indian businesses, and it keeps billing, stock and GST work in one place.

• Free HSN and SAC code finder. Search by item name or number, with no sign-up, on our HSN code finder. It gives codes only, not GST rates.
• GST billing. Make bills by voice in Hindi or English, or by barcode, on web, Android or iPhone.
• GST Center. Work on GSTR-1, GSTR-3B, e-way bill data and 2B reconciliation in the same app.
• Made for your trade. See how it fits hardware shops.

You can try WoveOS free for 15 days with every Pro feature on. After that you stay on the Free plan (50 bills a month), not a locked app: start free. See all plans on the pricing page.

FAQ

Is an HSN code required on every GST bill?

If your turnover is up to ₹5 crore, 4 digits are required on B2B bills and the code is optional on B2C bills. Above ₹5 crore, 6 digits are required on all bills. Exports need 8 digits.

What is the HSN code for cement?

The heading is 2523. Sub-heading 252329 covers other Portland cements. Commonly listed 8-digit codes include 25232910 for dry OPC and 25232930 for PPC. Check the code against your product and your supplier’s bill.

Does the HSN code decide my GST rate?

The code identifies the goods, and rates are notified with reference to it, so a wrong code can lead you to the wrong rate. Always confirm the current rate with the latest CBIC notification or your CA.

Sources

Note: this article is general information as of November 2026, not tax advice.

• StudyCafe, on Notification No. 78/2020 – Central Tax: studycafe.in
• Taxguru (30 Dec 2024), HSN/SAC reporting and PAN-wise turnover: taxguru.in
• Taxscan (31 May 2025), Table 12 B2B and B2C reporting: www.taxscan.in
• abcaus (1 May 2025), Phase-3 HSN reporting advisory: abcaus.in
• Global Cement (8 Sep 2025), GST on cement cut to 18%: globalcement.com
• Cement code listings, EximPe and Credlix: www.credlix.com