HSN and SAC codes on GST invoices: how many digits, and where to find them

Every line on a GST tax invoice carries a code that says what was sold: an HSN code for goods or an SAC code for services. The code decides the GST rate, it is how your buyer's accountant knows what they bought, and it rolls up into the HSN summary in your GSTR-1. This guide covers what the codes are, how many digits you need, and how to avoid the usual mistakes.

HSN codes for goods

HSN stands for Harmonized System of Nomenclature, the international classification used for customs. India uses it for GST, with up to 8 digits:

The first six digits are the same in every country that uses the Harmonized System; the last two are India's own.

SAC codes for services

SAC stands for Services Accounting Code. SAC codes are India's own and all start with 99. Most are written with 6 digits, for example:

Codes like these are examples to show the format; check the exact code for your service before you use it.

How many digits your invoices need

The number of digits depends on your aggregate turnover in the previous financial year:

Exporters and businesses dealing in goods that the government has specifically notified may need more digits. Using more digits than required is always allowed, and 6 digits is a sensible habit even below ₹5 crore.

How to find the right code

1. Start with what you sell, not the code list. Write down what the item is made of and what it is used for.
2. Search the GST portal's HSN/SAC search, which lists codes with their descriptions.
3. Check the rate schedule for that code. Codes and rates change from time to time, so check the rate that applies on the invoice date.
4. Keep a list. Once a code is settled for an item, save it with the item so every invoice uses the same one.
5. Ask your chartered accountant when an item could fit two headings. The difference can mean a different rate.

HSN codes and your GSTR-1

GSTR-1 includes an HSN-wise summary (Table 12): for each code and rate, the unit, total quantity, taxable value and tax. It uses the same digits as your invoices and is now split between supplies to registered buyers and to consumers. If the codes on your invoices are consistent, this table is simply a sum; if they are not, it is a headache every month.

The unit in the summary is a standard unit quantity code — NOS for numbers, KGS for kilograms, MTR for metres, and NA for services.

Common mistakes with HSN and SAC

• Guessing the code and, with it, the GST rate.
• Using an HSN code for a service or an SAC code for goods.
• Too few digits once turnover crosses ₹5 crore — the requirement is based on the previous year's turnover, so check it every April.
• Different codes for the same item on different invoices, which makes the GSTR-1 summary wrong.
• Leaving the code out on a B2B line, which your buyer's accountant will query.

How Invoice Native helps

• Each line has an HSN/SAC field next to its GST rate, and the code is checked for 4, 6 or 8 digits.
• When you set your turnover above ₹5 crore, issuing an invoice asks for 6 digits on every line; below it, B2B lines need a code.
• Saved items remember their code and rate, so they are the same every time.
• Signed-in businesses get an HSN/SAC summary report with units mapped to UQC codes, ready to check before filing.

Invoice Native checks the format of a code, not whether it is the right one for your product — that part stays with you and your accountant. For everything else a tax invoice must show, see the GST invoice format.