GST Invoice Format India: Complete Guide (2026)

Getting the GST invoice format right matters for two reasons: it's a compliance requirement, and a correctly formatted invoice gets processed and paid faster by clients' accounts teams. Here's the complete format, explained simply.

Mandatory Fields on a GST Invoice

Under GST rules, every tax invoice must include:

• Invoice number — unique, sequential, for the current financial year
• Date of issue
• Supplier's name, address, and GSTIN
• Recipient's name, address, and GSTIN (if registered)
• HSN code (goods) or SAC code (services)
• Description of goods or services
• Quantity (for goods) and unit
• Total value of goods/services (before tax)
• Taxable value (after any discount)
• GST rate and amount — CGST + SGST, or IGST
• Place of supply (for inter-state transactions)
• Total invoice value, including tax
• Signature of the supplier or authorized representative (digital signature is acceptable for e-invoices)

CGST + SGST vs. IGST

• Same-state transaction: split the GST between CGST (Central GST) and SGST (State GST), each at half the total rate.
• Inter-state transaction: charge IGST (Integrated GST) at the full rate instead.

Getting this wrong is one of the most common GST invoicing errors — always check the recipient's registered state, not just their billing address.

HSN and SAC Codes

• HSN (Harmonized System of Nomenclature) codes classify goods.
• SAC (Services Accounting Code) codes classify services.

The number of digits required depends on your annual turnover — businesses with higher turnover generally need to quote longer, more specific codes. Using the correct code matters for accurate GST return filing.

Common GST Rates (For Reference)

GST rates typically fall into slabs of 0%, 5%, 12%, 18%, and 28%, depending on the category of goods or service — always confirm the current rate for your specific HSN/SAC code, since rates are periodically revised by the GST Council.

Creating a GST-Compliant Invoice Online

• Open Simple Invoice Maker and add your GSTIN and business details.
• Add the client's GSTIN and confirm their state for the CGST/SGST vs. IGST split.
• Add line items with the correct HSN/SAC code and GST rate.
• Let the tool calculate the tax breakdown and total automatically.
• Download the PDF — formatted with all mandatory fields — and send it via email or WhatsApp.

FAQ

Is a GST invoice different from a regular invoice?

Yes — a GST (tax) invoice must include your GSTIN, HSN/SAC codes, and a clear tax breakdown (CGST/SGST or IGST), which a regular invoice doesn't require.

What happens if I use the wrong HSN/SAC code?

It can cause mismatches during GST return filing and may attract scrutiny during an audit — always verify the code for your specific product or service.

Can I generate a GST-formatted invoice for free?

Yes — Simple Invoice Maker's generator supports GST fields and calculates the tax breakdown automatically, for free.

Create your GST invoice now — free, with all mandatory fields built in.