HSN Codes Explained: How Many Digits You Need and How to Find Yours

5 min read · GST

The HSN code on your invoice quietly decides your GST rate — and how many digits you must show depends on your turnover. Here's what HSN and SAC are, and how to get the right one every time.

HSN vs SAC

HSN (Harmonised System of Nomenclature) classifies goods; SAC (Service Accounting Code) classifies services. Both are required on GST invoices and both map to a GST rate. HSN is a global standard, which is why the first six digits are the same worldwide.

How many digits must you show?

It depends on aggregate turnover: up to ₹5 crore → 4 digits (mandatory for B2B, optional for B2C); above ₹5 crore → 6 digits. Showing fewer digits than required, or a code that doesn't match the item, is a common cause of GSTR-1 mismatches.

The code fixes the rate

Because the HSN determines the rate, the two must always agree on the invoice. Cement is 28%, a laptop is 18%, packaged rice is 5%, unbranded flour is 0% — the code is what tells the system which. Guessing the rate without confirming the code is how businesses end up under- or over-charging GST.

Find your code in seconds → our free HSN / SAC code finder takes a product or service name and returns the code with its GST rate. Then raise the bill with the invoice generator.

When in doubt, check the notification

Most items sit at a standard 0/5/12/18/28% rate, but some carry conditional or notified rates that change with GST Council decisions. For edge cases, confirm against the latest CBIC rate notification before you bill.

Never look up an HSN again

OnGravy auto-fills the HSN and GST rate on every invoice line from your item master — and carries it into GSTR-1.

Try OnGravy →

General information, not tax advice. Rates change — confirm the current figure with your CA.