How to Create a Legally Compliant GST Invoice in India (GST 2.0 Rules)
Under the Indian Goods and Services Tax framework, issuing a compliant tax invoice is not merely good bookkeeping—it is a strict statutory mandate under Section 31 of the CGST Act, 2017. A single missing field, incorrect place of supply, or improper HSN code can lead to delayed payments and disqualification of your buyer's Input Tax Credit (ITC).
Following the landmark GST 2.0 reforms effective 22 September 2025, the tax slab architecture in India was streamlined into four primary tiers (0%, 5%, 18%, and 40%), removing the legacy 12% and 28% brackets. Here is everything suppliers, freelancers, and businesses need to know to generate fully valid GST tax invoices.
1. Mandatory Particulars on a Valid GST Tax Invoice
According to Rule 46 of the CGST Rules, every tax invoice issued by a registered taxpayer must explicitly include the following details:
- Supplier Details: Registered business name, trade name, registered office address, and 15-digit GSTIN.
- Consecutive Invoice Serial Number: A consecutive number containing only alphabets, numerals, and special characters (hyphen
-and slash/), unique for a given financial year. - Date of Issue: The date on which the invoice is generated and provided to the recipient.
- Recipient (Buyer) Details: Name, address, and GSTIN (if registered) or PAN. If the buyer is unregistered and invoice value exceeds ₹50,000, recipient name, address, and state must be recorded.
- Place of Supply (POS): The name of the state and 2-digit Indian state code (e.g., 27 for Maharashtra, 07 for Delhi) where supply is determined to take place.
- HSN / SAC Code: Harmonised System of Nomenclature code for goods or Service Accounting Code for services.
- Itemized Description & Quantities: Clear description of goods/services, unit measurement (UQC), quantity, rate per unit, and total taxable value before tax.
- GST Tax Rates & Breakup: Applicable GST 2.0 rate (0%, 5%, 18%, 40%, or special 3%/0.25%), showing exact CGST + SGST or IGST amounts separately.
- Signature / Digital Signature: Physical signature of authorized signatory or digital signature certificate (DSC) / electronic verification code.
2. Place of Supply: Intra-State vs. Inter-State Allocation
The determination of whether you charge Central GST + State GST or Integrated GST hinges strictly on the Place of Supply relative to the supplier's location:
- Intra-State Supply (Supplier State === Place of Supply): The tax amount is divided equally: 50% as Central GST (CGST) and 50% as State GST (SGST) or Union Territory GST (UTGST). For example, on an 18% slab item worth ₹10,000 supplied within Maharashtra, you charge ₹900 CGST and ₹900 SGST.
- Inter-State Supply (Supplier State !== Place of Supply): The full tax amount is charged as Integrated GST (IGST) and remitted to the Central Government. On the same ₹10,000 transaction billed from Maharashtra to Karnataka, you charge ₹1,800 IGST.
Need to verify pre-tax or post-tax totals? Cross-check your numbers instantly with our GST Calculator or Reverse GST Calculator.
3. HSN and SAC Digit Requirements
To standardize commodity classification, suppliers must declare HSN codes according to their Aggregate Annual Turnover (AATO):
| Aggregate Annual Turnover (AATO) | B2B Supplies | B2C Supplies |
|---|---|---|
| Up to ₹5 Crore | 4 Digits mandatory | Optional |
| Above ₹5 Crore | 6 Digits mandatory | 6 Digits mandatory |
| Export / Import (Cross-Border) | 8 Digits mandatory | 8 Digits mandatory |
4. Top 4 Costly GST Invoicing Mistakes to Avoid
- Incorrect Buyer GSTIN: Even a single typo in the 15-character alphanumerical GSTIN prevents auto-population in GSTR-2B, locking your customer out of their Input Tax Credit until an amendment table (Table 9) is filed in the subsequent return period.
- Using Deprecated 12% or 28% Slabs: Invoices issued after 22 September 2025 must adhere to the GST 2.0 rationalization. Ensure goods formerly classified under 12% or 28% are mapped to their revised 5%, 18%, or 40% brackets.
- Duplicate Serial Numbers: Every financial year (April 1 to March 31) must maintain an unbroken, non-repeating serial number sequence. Duplicate numbers trigger audit flags during annual reconciliation (GSTR-9C).
- Mismatched Taxable vs Gross Amounts: Mathematical rounding errors between line items and total amounts lead to discrepancies on the GSTN portal during GSTR-1 JSON upload.