HSN & SAC Codes Explained: How Many Digits Do You Need?

How many HSN digits you need depends entirely on your turnover: up to ₹5 crore in the preceding financial year, you need a 4-digit HSN code on B2B tax invoices; above ₹5 crore, you need 6 digits on every invoice. Services use a separate but parallel system — SAC codes, conventionally shown at 6 digits. Getting the code right matters because it's what determines the GST rate that applies.

What's the actual difference between HSN and SAC?

HSN (Harmonized System of Nomenclature) is an internationally standardized system for classifying goods — it's the same system used in customs and international trade, adapted for GST. SAC (Services Accounting Code) is India's parallel system specifically for classifying services. Every line item on a GST invoice needs one or the other, depending on whether you're billing goods or services — see our goods vs services invoice guide if you're not sure which applies to a specific line item.

How many digits does my invoice actually need?

"Aggregate turnover" here means your business's total turnover in the previous financial year, not the value of the individual invoice. SAC codes for services are conventionally shown at 6 digits regardless of turnover, following the same underlying classification depth as the 6-digit HSN tier.

Why does using the wrong code actually matter?

It's tempting to treat the HSN/SAC field as a formality, but the code is directly tied to the GST rate that legally applies to what you sold. A misclassified item can mean you've charged 12% when the correct rate was 18%, or vice versa — which creates a real under- or over-collection that has to be corrected, and can draw scrutiny in a review if it happens repeatedly or at scale. Treat the code as a rate lookup, not just a label.

Some common codes freelancers and small businesses use

These are illustrative examples only — always verify the exact code for your specific service on the GST portal's HSN/SAC search tool rather than copying an example, since service scopes can be classified differently depending on exact specifics:

How do I actually find the right code?

Three practical routes, roughly in order of reliability: (1) the GST portal's own HSN/SAC finder, which lets you search by keyword or browse by chapter/heading; (2) checking what code similar businesses in your trade association or industry body commonly use for the same service; (3) asking a tax professional to confirm, especially if your product or service could plausibly fall under more than one heading. Avoid relying purely on a code you found via a general web search without cross-checking it against the official portal. See our dedicated GST rate finder guide for a step-by-step walkthrough of this lookup process and how to read the results.

Does HSN/SAC change how much CGST, SGST or IGST I charge?

No — these are two independent parts of an invoice. HSN/SAC tells you what rate applies to the item; whether that tax is then split into CGST+SGST or charged in full as IGST depends purely on where the sale happens, covered fully in our CGST vs SGST vs IGST guide. The two decisions are made separately but both show up together on the invoice line.

For everything else a compliant invoice line needs alongside its HSN/SAC code, see the full GST invoice format checklist. QWIK INVOICE's invoice generator has a dedicated HSN field on every line item, so once you've confirmed the right code, it's reused automatically on future invoices for the same item.