GST invoicing for small shops & counters: what every bill must show

A GST invoice is more than a receipt. It is the document your customer uses to claim input tax credit, and the record you file from. Missing one field can mean a rejected credit for your customer — and an awkward phone call for you.

The fields a tax invoice must show

If you are a regular GST-registered business selling taxable goods or services, your tax invoice needs:

• Your name, address and GSTIN.
• A consecutive invoice number, unique for the financial year (up to 16 characters).
• The date of issue.
• The customer's name, address and GSTIN if they are registered.
• HSN code for goods or SAC code for services.
• Description, quantity and unit of measurement.
• Total value, any discount, and the taxable value.
• The tax rate and amount, split as CGST and SGST within your state, or IGST across states.
• Place of supply, with state name, for supplies to another state.
• Whether tax is payable on reverse charge.
• Your signature or digital signature/QR code.

Good billing software fills most of these for you. Your job is to make sure the business details and item codes are right once.

When to issue a bill of supply instead

If you are registered under the composition scheme, or you are selling only exempt goods or services, you issue a bill of supply, not a tax invoice. It does not show GST, because you are not charging it to the customer.

HSN and SAC codes

The number of digits you need depends on your annual turnover. Smaller businesses generally use 4 digits on B2B invoices; larger businesses use 6 to 8 digits. Set the code on each product or service once and let your billing system print it every time.

Walk-in customers & retail counters

For unregistered walk-in customers you don't need their GSTIN. For higher-value sales to unregistered customers, the invoice must also carry their name, address and the place of supply. inPos handles this smoothly by capturing customer details optionally or issuing rapid counter receipts.

E-invoicing

Businesses above the notified turnover threshold must generate B2B invoices through the government's Invoice Registration Portal, which returns an IRN and a QR code to print on the invoice. If you are close to the threshold, plan for it before you cross it.

A one-minute checklist

• Business name, address and GSTIN are correct in settings.
• Every product has an HSN or SAC code and a tax rate.
• Invoice numbers run in sequence and reset only at the financial year.
• Inter-state sales show IGST and the place of supply.
• You keep an immutable copy of every invoice, including cancelled ones.

inPos team
Written by the people who build inPos at Innerix Technologies, Kerala.