GST Invoice Format 2026 — Everything Indian Businesses Need to Know

If you run a business in India, issuing a correct GST invoice isn't optional — it's a legal requirement. A wrong format can lead to penalties, input tax credit rejections, and compliance headaches.

This guide covers the exact GST invoice format required in 2026, what fields are mandatory, and how to generate compliant invoices for free.

What is a GST Invoice?

A GST Invoice is a legal document issued by a registered supplier to the buyer. It serves as proof of sale and is essential for claiming Input Tax Credit (ITC).

Under the CGST Act 2017, every registered taxpayer must issue a GST invoice for:

• •Supply of goods worth more than ₹200
• •All supply of services
• •Exports and inter-state supplies

Mandatory Fields in a GST Invoice (2026)

| Field | Description | |-------|-------------| | Supplier Name & GSTIN | Your business name and 15-digit GST number | | Invoice Number | Unique, sequential, max 16 characters | | Invoice Date | Date of issue | | Buyer Name & GSTIN | Required for B2B transactions | | HSN/SAC Code | Harmonized code for goods/services | | Item Description | What you're selling | | Quantity & Unit | How much and in what unit | | Taxable Value | Amount before tax | | Tax Rate & Amount | CGST + SGST (intra-state) or IGST (inter-state) | | Total Amount | Final amount including tax | | Place of Supply | State where goods/services are delivered |

Common Mistakes to Avoid

1. •Wrong HSN/SAC codes — Use the correct 4-6 digit code for your product/service
2. •Missing GSTIN on B2B invoices — Always collect the buyer's GSTIN for B2B sales
3. •Non-sequential invoice numbers — GST requires sequential numbering within each financial year
4. •Incorrect tax calculation — Use CGST+SGST for same-state, IGST for different states

Generate Free GST Invoices Online

Instead of struggling with Excel templates, use HustleStack's free GST Invoice Generator to create compliant invoices in under 2 minutes:

• •✅ Auto-calculates CGST/SGST/IGST
• •✅ Professional PDF format
• •✅ HSN/SAC code support
• •✅ Download and share instantly
• •✅ 100% free, no registration needed

Conclusion

Getting your GST invoice format right protects your business from penalties and ensures your buyers can claim ITC. Whether you issue 5 invoices a month or 500, having a reliable invoice generator saves hours of manual work.

Generate your free GST invoice now →