The number of HSN digits required on a GST tax invoice depends on aggregate annual turnover: 4 digits for turnover up to Rs.5 crore and 6 digits for turnover above Rs.5 crore, per Notification 78/2020-Central Tax. Eight-digit HSN is required for specified chemicals and for exports/imports.
The turnover-based requirement
| Aggregate annual turnover (preceding FY) | HSN digits — B2B | HSN digits — B2C |
|---|---|---|
| Up to Rs.5 crore | 4 digits | 4 digits (optional in some cases) |
| Above Rs.5 crore | 6 digits | 6 digits |
This applies to tax invoices and to HSN-summary reporting in GSTR-1 (Table 12). SAC codes for services follow the same digit logic. Verify the latest position, as the portal has progressively tightened HSN reporting in GSTR-1.
When 8 digits are required
Eight-digit HSN is mandatory for a notified list of items (for example, certain chemicals) regardless of turnover, and for exports and imports, which follow the Customs Tariff at the 8-digit level. Using a shorter code for these can hold up shipping-bill and refund processing.
Why the right HSN matters
- HSN drives the rate of GST — a wrong code can mean wrong tax and a demand.
- GSTR-1 Table 12 now validates HSN; mismatches block or warn on filing.
- Customers reconcile HSN for their own classification and ITC eligibility.
- Use the HSN/SAC Finder to confirm the code and rate before invoicing.
Practical setup in your accounting system
Map each item master to its correct HSN/SAC and GST rate once, and lock it, so invoices and GSTR-1 carry consistent codes. For mixed portfolios near the Rs.5 crore line, default to 6 digits to stay compliant as turnover grows, rather than re-tagging masters mid-year.
Key takeaways
- Up to Rs.5 crore turnover: 4-digit HSN; above Rs.5 crore: 6-digit.
- 8 digits for notified items and for exports/imports.
- GSTR-1 Table 12 validates the HSN summary.
- Map item masters to HSN/SAC and rate once to keep invoices consistent.