The Architecture of an Enforceable Indian Retail Bill: Rule 46 vs. Rule 49
If you run a retail shop, wholesale distribution counter, or restaurant in India, issuing a piece of paper that simply says "Cash Bill" with a stamped total is no longer adequate protection. Under Chapter VI of the Central Goods and Services Tax (CGST) Rules, 2017, the document you hand to a customer is a legal commercial instrument that determines liability, tax audit safety, and input credit validity.
The first structural decision every business owner must make is whether they are legally mandated to issue a Tax Invoice or a Bill of Supply:
| Parameter | Tax Invoice (Rule 46) | Bill of Supply (Rule 49) |
|---|---|---|
| Eligible Taxpayer | Regular GST registered dealers charging CGST, SGST, or IGST. | Composition Scheme dealers (turnover up to ₹1.5 Cr) or merchants dealing purely in 100% exempt/nil-rated goods. |
| Tax Collection | Mandatory to display tax rates and collect tax separately from buyer. | Strictly prohibited from charging any GST to the customer. |
| Mandatory Declaration | Displays "Tax Invoice" prominently with supplier GSTIN. | Must state: "Composition taxable person, not eligible to collect tax on supplies". |
| Buyer Input Credit | Yes; B2B buyers can claim Input Tax Credit (ITC) using supplier GSTIN. | No; buyers cannot claim any tax credit on a Bill of Supply. |
The 16 Mandatory Fields Under GST Rule 46
When state commercial tax officers inspect a retailer's records during a survey or scrutiny, technical defects in bill numbering and tax categorization are the most frequent sources of compounding penalties under Section 122. A bulletproof Indian tax invoice must contain:
- Consecutive Serial Numbering: Must not exceed 16 characters, containing only letters, numerals, and special characters (hyphen
-and slash/). Crucially, the series must be unique for each financial year (e.g.,2026-27/001). Breaking serial continuity or running multiple parallel unrecorded bill series invites immediate tax scrutiny. - Date of Issue: Must correspond to or precede the removal of goods from the store counter (Section 31(1)).
- Supplier Identification: Legal registered name, trading style, operational address, and 15-digit GSTIN.
- Recipient Details: For B2B transactions or any supply exceeding ₹50,000, recipient name, delivery address, state code, and GSTIN are compulsory. For counter cash sales under ₹50,000, un-named retail cash memos are legally valid.
- Harmonized System of Nomenclature (HSN):
- Turnover up to ₹5 Crores in preceding financial year: 4-digit HSN code mandatory for B2B invoices (optional for B2C).
- Turnover exceeding ₹5 Crores: 6-digit HSN code mandatory for all tax invoices.
- Statutory Tax Split: In intra-state supplies, never combine tax into a single "GST 18%" line. Rule 46 requires distinct columns for CGST (9%) and SGST (9%) to facilitate state revenue allocation.
58mm and 80mm Thermal Receipts: Operational Reality vs. Statutory Audits
More than 80% of Indian high-footfall businesses—including grocery marts, bakeries, medical counters, and quick-service restaurants (QSR)—rely on compact thermal line printers rather than A4 laser printers. While thermal printers offer 2-second printing and zero ink expense, business owners often make critical compliance errors:
- Thermal Paper Fading: Standard thermal rolls fade completely within 6 to 9 months under Indian ambient heat and humidity. Under Section 36 of the CGST Act, every registered business must maintain accounts and records for 72 months (6 years) from the due date of filing the annual return. If you print thermal receipts at your counter, your billing software (or KhataOS) must preserve immutable digital records in local SQLite storage so that an auditor can inspect past ledger entries five years down the road.
- Line Truncation on 58mm Rolls: A 58mm roll gives you roughly 32 to 34 characters per line at font size 12. If item descriptions or HSN digits wrap awkwardly, price columns can misalign. The preview generator above automatically shifts to condensed receipt formatting when 58mm mode is active.