GST Invoice: Format, Rules, Types & Mandatory Details Explained

Introduction

Invoicing in business is more than just documentation—it plays a vital role in maintaining financial accuracy, GST compliance, and transparent accounting across operations.

After the implementation of the Goods and Services Tax (GST), all registered businesses are required to issue GST-compliant invoices, also known as GST bills. Since every transaction is recorded through invoices in the books of accounts, it is essential to generate them correctly and in accordance with GST rules.

This article explains everything about GST invoicing, including its meaning, who should issue it, mandatory details, types of invoices, revised invoices, and special cases under GST law.

Key Takeaways

A GST invoice must include key details such as invoice number, date, supplier and recipient GSTIN, place of supply, and item-wise description
For unregistered customers, invoices exceeding ₹50,000 require additional recipient details
The CGST Act specifies timelines for issuing invoices, revised invoices, debit notes, and credit notes
A Bill of Supply is issued when GST is not applicable, such as for exempt goods or composition scheme taxpayers
An Invoice-cum-Bill of Supply is used for mixed supplies involving both taxable and exempt goods/services supplied to unregistered persons

What is a GST Invoice? Meaning, Definition & Importance

In simple terms, a GST invoice (also known as a GST bill) is an official document issued by a GST-registered supplier that contains details of goods supplied or services provided, along with the amount payable.

A GST invoice includes all mandatory particulars prescribed under the CGST Rules and is issued at the time of sale of goods or services. It serves as legal proof of a transaction and plays a key role in ensuring GST compliance.

A GST invoice is also essential for buyers, as it allows them to claim Input Tax Credit (ITC), thereby reducing their overall tax liability.

In addition, the invoice records the time of supply, which is important for determining the correct point of taxation under GST law.

Who Should Issue a GST Invoice? Applicability Explained

All businesses registered under the CGST Act, regardless of their size or turnover, are required to issue a GST-compliant invoice when supplying goods and/or services. Every taxable sale must be documented through a proper GST invoice as per the prescribed rules.

On the other hand, buyers should also ensure they receive valid GST invoices from their vendors. This is essential for claiming Input Tax Credit (ITC) and maintaining full GST compliance.

Issuing and collecting proper GST invoices helps ensure transparency, accurate tax reporting, and seamless credit flow in the GST system.

Mandatory Fields of a GST Invoice: Complete List

A tax invoice under GST is issued to charge tax on supplies and enable the buyer to claim Input Tax Credit (ITC). To ensure compliance, every GST invoice must include specific mandatory details prescribed under GST law.

Essential Mandatory Fields in a GST Invoice

A GST-compliant invoice must include the following information:

Invoice number (unique serial number)
Invoice date
Name of the customer
Billing and shipping address
GSTIN of both supplier and customer (if registered)
Place of supply
HSN code (for goods) or SAC code (for services)
Description of goods/services
Quantity and unit of measurement (kg, meter, etc.)
Total invoice value
Taxable value and applicable discounts
GST rate and tax breakup (CGST, SGST, IGST)
Mention of reverse charge applicability (if any)
Signature of the supplier or authorized person

Additional Details for Unregistered Customers

If the recipient is not registered under GST and the invoice value exceeds ₹50,000, the invoice must also include:

Name and address of the recipient
Delivery address
State name and state code

Including all these details ensures the invoice is valid under GST law and supports seamless Input Tax Credit claims and tax compliance.

Bill of Supply: Meaning, Applicability & Rules under GST

A Bill of Supply is similar to a GST invoice, but it does not include any tax details, as the supplier is not permitted to charge GST from the buyer in such cases.
A Bill of Supply is issued when GST cannot be levied on the transaction, such as:
When a registered person supplies exempted goods or services
When a taxpayer has opted for the Composition Scheme under GST
Invoice-cum-Bill of Supply
As per Notification No. 45/2017 – Central Tax dated 13th October 2017, if a registered taxpayer supplies both taxable and exempt goods or services to an unregistered person, they are allowed to issue a combined document known as an “Invoice-cum-Bill of Supply.”
This single document covers all types of supplies in one invoice, simplifying compliance for mixed transactions under GST.

Aggregate Invoice under GST: Meaning and Example

An aggregate invoice is a consolidated invoice that a supplier can issue when multiple small invoices are raised in a single day for an unregistered buyer.

Under GST rules, if the value of individual invoices is less than ₹200 each, the supplier is allowed to combine them and issue a single bulk or aggregate invoice on a daily basis instead of issuing separate invoices.

Example of Aggregate Invoice

For instance, if a supplier issues three invoices in a day of ₹80, ₹90, and ₹120, all to an unregistered customer, they can issue one combined invoice of ₹290. This consolidated document is known as an aggregate invoice.

This provision helps businesses reduce paperwork and simplify invoicing for small-value transactions under GST.

About the Author

Dakesh

Dakesh breaks down complex legal regulations into clear, actionable guidance, helping entrepreneurs stay compliant while building sustainable and scalable businesses.

May 5, 2026