Learn everything about GST invoice format, mandatory fields, and compliance requirements for Indian businesses.
· GST · 5 min read
What is a GST Invoice?
A GST invoice is a tax document issued by a registered business to a buyer when goods or services are supplied. It is mandatory under the GST Act for businesses with annual turnover exceeding the threshold limit.
Mandatory Fields in a GST Invoice
Every GST invoice must contain the following details:
- Supplier Details: Name, address, and GSTIN of the supplier
- Invoice Number: A unique sequential number
- Date of Issue: The date when the invoice is issued
- Recipient Details: Name, address, and GSTIN (if registered)
- Description of Goods/Services: HSN code for goods, SAC code for services
- Quantity and Unit: Number of units and measurement
- Total Value: Total amount before tax
- Taxable Value: Amount after discounts
- Rate of Tax: CGST, SGST, or IGST rates
- Place of Supply: State name and code
- Signature: Digital or physical signature of the supplier
CGST/SGST vs IGST
- Intra-state supply (same state): Charge CGST + SGST (each at half the GST rate)
- Inter-state supply (different states): Charge IGST (full GST rate)
Example
For a service worth ₹10,000 with 18% GST in Maharashtra:
- CGST (9%): ₹900
- SGST (9%): ₹900
- Total: ₹11,800
For the same service supplied to a client in Delhi:
- IGST (18%): ₹1,800
- Total: ₹11,800
How Invoice Mitra Helps
Invoice Mitra automatically calculates CGST/SGST vs IGST based on whether the supplier and recipient are in the same state. Just enter the details and download a compliant invoice.
FAQ
Do I need an HSN code on every GST invoice? Goods need a 4-digit HSN code; services need a 6-digit SAC code. If your turnover is below ₹1.5 crore, HSN codes are optional but recommended.
Can I use one invoice for both CGST/SGST and IGST? No. Intra-state supplies use CGST+SGST; inter-state supplies use IGST. Mixing them on one invoice will cause filing errors.
Who signs the GST invoice? The supplier or an authorised person must sign — digitally or physically — for the invoice to be valid.
Two things usually slow people down after the numbers are right. The first is the HSN or SAC code, because a goods line needs a four-digit HSN code and a service line needs a six-digit SAC code — the HSN and SAC code finder lists both. The second is the layout itself: which columns to keep separate so the tax never has to be back-calculated. That is covered in the GST invoice format guide, including the storage mistakes that make a spreadsheet invoice fail at filing time.
Create your free GST invoice now at invoicemitra.in