Check the HSN digit requirement using the applicable notification, the preceding financial year's aggregate turnover and the recipient category. CBIC's guidance on Notification 78/2020-Central Tax explains the requirements effective from 1 April 2021: four digits for the covered lower turnover band on B2B invoices and six digits for taxpayers above ₹5 crore in the preceding financial year. Confirm the current notification and any specific requirements before applying a blanket rule to every document.
Use aggregate turnover, not one branch's sales
The threshold refers to aggregate turnover, a defined GST concept. Do not substitute the sales of one counter, one State registration or the taxable value in one return without checking the statutory calculation. Keep the approved turnover working and the financial year used for the decision.
For a business with registrations in two States, a small branch may be part of a PAN-level business whose aggregate turnover exceeds the relevant band. Staff should receive the approved disclosure setting rather than calculate it independently from their local monthly sales. This avoids different branches choosing different code depths from incomplete figures.
Read the boundary carefully
The notification's turnover table uses “up to” ₹5 crore and “more than” ₹5 crore. A value exactly at ₹5 crore belongs to the former band under that wording. Retain actual figures rather than a rounded label such as “about five crore,” because a small difference can change the disclosure requirement.
| Preceding-year turnover position under the notification | General invoice disclosure check |
|---|---|
| Up to ₹5 crore | Four-digit HSN requirement, with the unregistered-recipient relaxation to review |
| More than ₹5 crore | Six-digit requirement for the covered taxable supply invoices |
CBIC's accompanying explanation also addresses SAC for taxable services. For a service item, use the appropriate service classification and applicable disclosure requirements rather than inventing an HSN by formatting a service description as goods.
Check the unregistered-recipient relaxation
Notification 78/2020 allows a registered person in the up-to-₹5-crore band not to mention the specified HSN digits on tax invoices for supplies to unregistered persons. That is a disclosure relaxation, not an exemption from classifying goods correctly or charging the appropriate tax.
Confirm that the buyer is actually unregistered. A GSTIN omitted from an incomplete order does not establish B2C status. If a business customer requests invoicing to its registration, obtain and verify the details before choosing the lower-band unregistered treatment. Keep customer status and turnover settings as separate controls.
Illustrative two-year review
Suppose a business's approved aggregate turnover for FY 2025–26 is ₹4.70 crore. It reviews its invoice disclosure setting for FY 2026–27 using that preceding-year figure. It does not switch to the above-₹5-crore setting merely because a large new order is expected in November; it checks the notification's stated test and any other applicable requirements.
If its approved preceding-year turnover for a later year is ₹5.40 crore, the six-digit band needs review for that later year's invoices. Record the date the setting changes and test all active billing channels. A shop counter, service billing screen and imported order file can retain different defaults unless the update is applied consistently.
Do not confuse invoice rules with return validations
An invoice code requirement and a portal's HSN reporting or validation rules are related but not identical. GSTN may prescribe return-table formats, code selection or other validations that require separate checking for the relevant return period. A document that satisfies one invoice disclosure relaxation is not automatically exempt from every reporting requirement.
Likewise, customs, e-way bill or other transaction requirements can demand information beyond the minimum printed invoice field. Maintain the researched full classification in the master and configure each output according to its applicable requirement. Deleting code detail from the master to simplify the customer bill can create avoidable reporting problems.
Validate real codes, not just character counts
A four-digit string must represent the correct heading, and a six-digit string must represent the correct subheading or relevant service classification. Adding two zeros to meet a length check does not establish validity. Compare the code with the official classification structure and the item description.
Use a sample of high-volume and newly introduced items to check the displayed code. Store codes as text so leading zeros survive spreadsheet exports. Review the printed invoice and structured data separately: a field can be correct in the database but clipped in a narrow PDF column or reformatted by an integration.
Include an invoice from a newly created item in the annual test. Older items may already carry detailed codes voluntarily, hiding an incorrect default for new products. Also check imports from spreadsheets: a cell formatted as a number can remove a leading zero even when the manually entered items remain correct.
Keep an annual decision note
Before the new financial year's invoicing begins, record the preceding-year turnover calculation, applicable notification, customer categories and approved settings. Assign responsibility for updating channels and checking the first issued documents. Retain the previous year's setting so older invoice records remain understandable.
A useful HSN-digit review ends with a documented disclosure decision and a tested output. It should also preserve the deeper classification evidence needed to determine the actual tax treatment. The number of digits is a visible compliance detail; the code must still describe the goods or services supplied.