GST Invoice Format in India —
Every Mandatory Field
The 16 fields a tax invoice must carry under Rule 46, the difference between a tax invoice and a bill of supply, B2B vs B2C rules, issue time limits and the e-invoicing threshold.
A GST tax invoice has no prescribed design, but under Rule 46 of the CGST Rules, 2017 it must carry 16 mandatory fields — including the supplier's GSTIN, a unique serial number (max 16 characters), the recipient's GSTIN for B2B, HSN/SAC code, taxable value, the GST rate and CGST/SGST/IGST shown separately, and the place of supply. You may build it in Excel, Tally or any billing app as long as every required field is present.
16 Mandatory Fields on a GST Invoice
These are the fields prescribed under Rule 46. Missing or wrong details can invalidate the invoice, block the buyer's Input Tax Credit and attract a penalty of up to ₹25,000 per invoice under Section 122.
| # | Field | What it must show |
|---|---|---|
| 1 | Supplier name, address & GSTIN | Registered details exactly as on the GST portal |
| 2 | Consecutive serial number | Unique within the financial year · maximum 16 characters |
| 3 | Date of issue | Date the invoice is raised |
| 4 | Recipient name, address & GSTIN | GSTIN mandatory for B2B; optional for B2C |
| 5 | Place of supply | State/UT code — decides CGST+SGST or IGST |
| 6 | HSN / SAC code | 4-digit up to ₹5 cr turnover, 6-digit above ₹5 cr |
| 7 | Description of goods / services | Clear description of the supply |
| 8 | Quantity & unit | For goods — quantity and unit (pcs, kg, mtr) |
| 9 | Total value of supply | Gross value before discount |
| 10 | Taxable value | Value after discount — GST is charged on this |
| 11 | Rate & amount of tax | CGST / SGST / UTGST / IGST shown separately |
| 12 | Total tax charged | Sum of all tax components |
| 13 | Reverse charge indication | Whether tax is payable under RCM |
| 14 | Signature / digital signature | Of the supplier or authorised signatory |
| 15 | State name & code | For supplier and recipient |
| 16 | Address of delivery | If different from the billing address |
Rule 46, CGST Rules 2017. GST rates on the invoice follow the GST 2.0 two-slab structure (5% / 18% + 40% demerit) effective 22 September 2025.
The invoice serial number must be consecutive and unique within a financial year, up to 16 characters, using letters, digits and special characters like "/" or "-". Gaps, resets mid-year or duplicate numbers are a common reason GST officers disallow ITC to the buyer.
Tax Invoice vs Bill of Supply, B2B vs B2C
A tax invoice is issued for taxable supplies. A bill of supply replaces it when you sell exempt goods or are a composition dealer who cannot charge GST. What changes between B2B and B2C is mainly whether the buyer's GSTIN is captured.
| Aspect | B2B (registered buyer) | B2C (unregistered buyer) |
|---|---|---|
| Buyer GSTIN | Mandatory | Not required |
| Document | Full tax invoice always | Tax invoice / consolidated bill |
| GSTR-1 reporting | Invoice-wise B2B table | Summary; B2C-large (inter-state > ₹1L) invoice-wise |
| Buyer ITC | Available | Not available |
| QR code | Via e-invoice IRP if applicable | Dynamic QR if turnover > ₹500 cr |
Composition dealers and sellers of exempt goods issue a Bill of Supply, not a tax invoice.
For B2B sales, always capture the buyer's correct GSTIN and place of supply — these two fields decide whether you charge IGST or CGST+SGST and whether your customer can claim the credit. A single wrong GSTIN can strand their ITC and trigger a reconciliation query.
Setting up GST-compliant invoicing for your business?
Talk to a GST Expert →Time Limit & Copies of a GST Invoice
The deadline to raise a tax invoice depends on whether you supply goods or services:
- Goods: on or before removal / delivery of the goods.
- Services: within 30 days of supply (45 days for banks and NBFCs).
- Continuous supply: at each due date or statement date under the contract.
Copies required: 3 for goods (original for buyer, duplicate for transporter, triplicate for supplier) and 2 for services (original for recipient, duplicate for supplier).
How Tax Appears on the Invoice
Intra-state supply (CGST + SGST)
Inter-state supply (IGST)
Within a state, 18% GST is split as 9% CGST + 9% SGST; across states it is a single 18% IGST. The place of supply on the invoice is what determines which applies. Use the GST calculator to check any value.
E-Invoicing — How It Works
E-invoicing is mandatory for taxpayers whose aggregate annual turnover exceeded ₹5 crore in any year from FY 2017-18 onwards. It does not replace your invoice format — you keep raising invoices, but each B2B invoice is reported to the government portal for validation.
- The IRN is a 64-character unique hash generated per invoice and must be printed on it.
- A QR code is mandatory on every e-invoice for verification.
- E-invoices must be reported to the IRP within 30 days of the invoice date for large taxpayers.
Debit Note vs Credit Note
| Document | When issued | Effect on tax |
|---|---|---|
| Debit note | Value under-billed on the original invoice | Increases supplier's tax liability |
| Credit note | Value over-billed / goods returned / discount | Reduces supplier's tax liability |
Both must quote the original invoice number and date. A credit note must be issued by 30 November of the following financial year or the annual-return date, whichever is earlier.
GST Invoice Compliance Checklist
- Supplier GSTIN & legal name
- Unique serial number (≤16 chars)
- Correct buyer GSTIN (B2B)
- Place of supply & state code
- HSN / SAC at the right digit level
- Taxable value after discount
- CGST / SGST / IGST shown separately
- Reverse-charge flag where relevant
- Signature / DSC of signatory
- IRN & QR code (if e-invoicing)
- Issued within the time limit
- Reported in GSTR-1
Frequently Asked Questions
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