How to Upgrade From a Kaccha Bill to a Pakka Bill (GST Invoice)

A kaccha bill is missing the things that make a bill a tax invoice: a GSTIN, a tax breakup, a classification code, a proper number. The upgrade is just adding those, in order. The first step is a one-time registration; the rest is a template you set once.

Four moves take a rough slip to a valid pakka bill:

• →1. Get a GSTIN. If your turnover crosses the registration threshold, or you want to issue tax invoices, register on the GST portal. The result is your 15-character GSTIN, the first field every tax invoice must carry.
• →2. Add the Rule 46 fields. A pakka bill needs your GSTIN, a unique invoice number, the buyer details, the taxable value, and the CGST/SGST or IGST split shown separately. See the full Rule 46 field set.
• →3. Set the right HSN or SAC code. Each line needs an HSN code for goods or a SAC code for services, because the code fixes the GST rate. A wrong code is a wrong rate and a return mismatch.
• →4. Number invoices in sequence. Run one continuous serial number per financial year, up to 16 characters. A broken or repeated series is a standard audit flag.

• →The hard part of the old kaccha habit was effort, not law. A generator removes the effort, so the compliant route is now the easy route.
• →Save your GSTIN, business details, and the codes for what you sell once; every later invoice reuses them, query-proof from the first download.
• →If you are below the threshold, unregistered, or under composition, you cannot charge GST, so you issue a bill of supply instead, not a kaccha bill.

• →A registered seller who keeps issuing kaccha slips understates turnover and denies buyers their input tax credit, weakening the relationship and the books at once.
• →For the full case on what you gain, see why move from a kaccha bill to a pakka bill.
• →Why it matters: the upgrade is a one-time setup against an ongoing risk. Done once, every future bill is correct by default.