Under the GST Act, every tax invoice must contain specific fields to be considered valid. Missing even one field can make your invoice non-compliant, which means your buyer cannot claim Input Tax Credit (ITC).
Here's a complete checklist of all 13 mandatory fields required in a GST invoice, as per Rule 46 of the CGST Rules, 2017.
The 13 Mandatory Fields
1. Supplier's Name, Address & GSTIN
The invoice must clearly show the registered name, address, and 15-digit GSTIN of the supplier (seller).
2. Invoice Number
A unique, consecutive serial number. It can contain alphabets, numerals, and special characters like hyphens or slashes. Must not exceed 16 characters. Must be unique within a financial year.
3. Date of Invoice
The date on which the invoice is issued. For goods, this should be on or before the date of removal/delivery.
4. Recipient's Name, Address & GSTIN
If the buyer is GST-registered, their GSTIN must be mentioned. If unregistered, the name and address are sufficient.
5. HSN Code / SAC Code
Harmonized System of Nomenclature (HSN) code for goods or Services Accounting Code (SAC) for services. The number of digits required depends on your turnover:
| Annual Turnover | HSN Digits Required |
|---|---|
| Up to ₹5 Crore | 4 digits |
| Above ₹5 Crore | 6 digits |
6. Description of Goods or Services
A clear description of what is being sold — e.g., "Cotton T-shirt (Round Neck, Size L)" or "Web Development Services."
7. Quantity & Unit
The quantity of goods supplied along with the unit of measurement (pieces, kg, litres, hours, etc.).
8. Total Value of Supply
The total value before applying taxes and after accounting for any discounts.
9. Taxable Value
The value on which tax is calculated — typically the total value minus any discounts.
10. Tax Rate
The applicable GST rate — broken down as CGST + SGST (for intra-state) or IGST (for inter-state).
11. Tax Amount
The actual rupee amount of tax charged, broken into CGST, SGST, or IGST components.
12. Place of Supply
The state where the goods are delivered or services are consumed. This determines whether CGST+SGST or IGST applies.
13. Signature of the Supplier
The invoice must bear the signature (physical or digital) of the supplier or their authorized representative.
BillCraft Tip
BillCraft automatically includes all 13 mandatory fields in every invoice. Just fill in your details, and the format handles compliance for you.
What Happens If Fields Are Missing?
- The buyer cannot claim Input Tax Credit
- The invoice may be rejected during GST audit
- Penalties may be imposed for non-compliance
- Returns (GSTR-1, GSTR-3B) may show mismatches
Quick Compliance Checklist
- ✓ Supplier GSTIN and address
- ✓ Unique invoice number (max 16 characters)
- ✓ Invoice date
- ✓ Buyer GSTIN (if registered)
- ✓ HSN/SAC codes
- ✓ Item description, quantity, unit
- ✓ Total value and taxable value
- ✓ Tax rate and tax amount (CGST/SGST/IGST)
- ✓ Place of supply
- ✓ Supplier's signature