GST Invoice Format India: Mandatory Fields, Rules & Sample Template (2026)

⚡ Core Rules of GST Tax Invoicing in India

1. Rule 46 Compliance

Every registered taxpayer issuing a tax invoice must include consecutive serial numbers (≤16 chars), GSTIN, HSN/SAC codes, and Place of Supply.

2. Tax Type: Intra vs Inter State

Charge CGST + SGST (equal 50/50 split) for sales within your home state. Charge IGST (single combined tax) for sales to clients outside your state.

3. Amount in Words

The gross invoice total must always be written in figures and spelled out in words to prevent reconciliation discrepancies and credit disputes.

Deep-Dive: Indian GST Invoicing Requirements Under Rule 46

Under Section 31 of the Central Goods and Services Tax (CGST) Act, 2017 read with Rule 46 of the CGST Rules, every registered business or independent professional supplying taxable goods or services must issue a formal Tax Invoice. A compliant invoice is essential for the recipient to claim Input Tax Credit (ITC) under Section 16.

1. Mandatory Fields on a Valid GST Invoice

To ensure statutory compliance, an Indian GST invoice must clearly show:

Supplier Details: Legal Name or Registered Business Name, Address, and 15-digit Goods and Services Tax Identification Number (GSTIN).
Invoice Number: A consecutive serial number not exceeding 16 characters (which may contain letters, numerals, and special characters '-' or '/'), unique for each financial year.
Date of Issue: The date on which the invoice is generated and provided to the recipient.
Recipient Details: Name, Billing/Shipping Address, and GSTIN or Unique Identification Number (UIN) if registered. For unregistered clients on B2C sales above ₹50,000, recipient name, address, and state code are mandatory.
Place of Supply (POS): Name of the destination State along with its official 2-digit State Code (e.g., Karnataka: 29, Maharashtra: 27, Delhi: 07).
HSN / SAC Code: Harmonized System of Nomenclature code for goods, or Services Accounting Code (SAC) for services.
Itemized Details: Description of goods/services, quantity, unit rate, and total taxable value after discounts.
Tax Breakdown: Applicable GST rate slab (0%, 5%, 12%, 18%, 28%) and the computed tax amount categorized as CGST + SGST (intra-state) or IGST (inter-state).
Total Amount: Gross total payable, stated in numerical figures and fully converted to words in Indian Rupees.
Signature: Authorized physical signature or verified digital signature of the supplier or power-of-attorney holder.

2. Intra-State vs Inter-State Tax Determination

The tax charged depends strictly on the relationship between the Location of the Supplier and the Place of Supply (POS):

Supply Category	Condition	Taxes Charged	Example (18% Slab)
Intra-State Supply	Supplier & Recipient in Same State	CGST (Central) + SGST (State)	9% CGST + 9% SGST
Inter-State Supply	Supplier & Recipient in Different States	IGST (Integrated Tax)	18% IGST

3. Annotated Fictional Sample GST Invoice

Below is an illustrative standard invoice for IT consulting services provided by a registered developer in Karnataka to a client in Maharashtra (Inter-State):

Supplier: TechCraft Studios (Karnataka - 29) \| GSTIN: 29AAAAA1111A1Z5		Invoice No: INV-2026-089 \| Date: 15 Aug 2026
Service Description	SAC Code	Rate / GST %	Amount (₹)
Custom Web App Architecture & Development	998314	₹50,000 (18%)	₹50,000
Taxable Value			₹50,000
Integrated GST (IGST 18% - Inter-State to Maharashtra 27)			₹9,000
TOTAL INVOICE VALUE (IN WORDS): Rupees Fifty-Nine Thousand Only		₹59,000

Editorial Transparency & Legal Sources

Last Reviewed: 19 September 2026

Reviewed by: SmartPaisa Tools Commercial Tax & Invoicing Team

Official Authorities: Central Board of Indirect Taxes and Customs (CBIC), GST Council Portal.

Review our Editorial Guidelines and General Disclaimer.

Frequently Asked Questions

Q1: What are the mandatory fields required on a GST Tax Invoice in India?

Under Rule 46 of the Central Goods and Services Tax (CGST) Rules 2017, a tax invoice must contain: Supplier Name, Address & GSTIN; Consecutive Serial Number (up to 16 alphanumeric characters); Date of Issue; Recipient Name, Address & GSTIN (if registered); Place of Supply with State code; HSN or SAC code; Description of goods/services; Taxable value; Tax rate (5%, 12%, 18%, 28%); Total tax split (CGST+SGST or IGST); and Signature/Digital signature of the authorized signatory.

Q2: When do I charge CGST + SGST versus IGST on a GST invoice?

For intra-state supplies (where the supplier's location and the Place of Supply are in the same Indian state), you charge CGST and SGST equally (e.g., 9% CGST + 9% SGST for an 18% rate). For inter-state supplies (where the supplier and recipient/Place of Supply are in different states), you charge IGST (Integrated GST) at the full 18% rate.

Q3: What is the maximum character limit for a GST invoice serial number?

Under GST rules, invoice serial numbers can contain up to a maximum of 16 characters consisting of letters, numbers, and special characters (hyphen '-' and slash '/'). Each invoice number must be unique within a given financial year.

Q4: What is the difference between HSN and SAC codes?

HSN (Harmonized System of Nomenclature) is an internationally standardized code used to classify physical goods and commodities. SAC (Services Accounting Code) is a 6-digit code issued by CBIC specifically used to classify services (such as IT consulting, marketing, legal, or construction services).

Q5: Why must the invoice total be written in words as well as numbers?

Writing the total invoice amount in words (e.g. 'Rupees Fifty-Nine Thousand Only') prevents fraudulent alterations or typographic misinterpretations of decimal places and commas in financial accounting, auditing, and input tax credit (ITC) claims.

GST Invoice Format in India: Mandatory Fields & Tax Split Rules