Running a business in India means GST is a daily reality. Whether you're a pharmacy in Ludhiana or a hotel in Udaipur, every invoice must meet GSTN requirements — or you risk penalties and blocked input tax credit for your customers.
This guide breaks down everything you need to know about GST billing in 2025.
The Basics: CGST, SGST, and IGST
GST in India is a dual-tax system:
- Intra-state transactions (seller and buyer in the same state): CGST + SGST, split equally. So 18% GST = 9% CGST + 9% SGST.
- Inter-state transactions (seller and buyer in different states): IGST only. 18% GST = 18% IGST.
Your billing software should detect the buyer's state from their GSTIN and apply the correct tax type automatically. Manual calculation is error-prone and slow.
What a Valid GST Invoice Must Contain
A GST-compliant invoice must include:
- Supplier's name, address, and GSTIN
- Invoice number (sequential, no gaps)
- Date of issue
- Buyer's name, address, and GSTIN (for B2B)
- HSN/SAC code for each item or service
- Quantity, unit price, and total
- CGST/SGST or IGST amount clearly separated
- Total invoice value in words
Missing any of these elements can invalidate the invoice for ITC (Input Tax Credit) purposes.
E-Invoicing: Who Needs It?
As of 2025, e-invoicing is mandatory for businesses with annual turnover above ₹5 crore. This means every invoice must be uploaded to the Invoice Registration Portal (IRP) and assigned an IRN (Invoice Reference Number) and QR code before being shared with the buyer.
GoClixy handles this integration automatically for eligible tenants — you generate the invoice in GoClixy, and the system pushes it to IRP and embeds the QR code before printing.
Common GST Billing Mistakes (and How to Avoid Them)
Wrong GSTIN on invoices: Always validate the buyer's GSTIN before saving. GoClixy validates GSTINs against the GSTN API in real time.
Missed HSN codes: Each product in your catalog must have the correct HSN code. GoClixy's product master stores HSN codes and applies them automatically to every invoice.
Invoice number gaps: GSTN flags gaps in invoice sequences. GoClixy maintains a continuous, tamper-proof invoice sequence per financial year.
Wrong tax type: Applying SGST+CGST to an inter-state sale (or IGST to an intra-state sale) creates reconciliation issues in GSTR-1. Automated tax type detection prevents this.
How GoClixy Simplifies GST Billing
GoClixy was built from day one for Indian GST compliance:
- Auto-applies CGST/SGST or IGST based on supplier and buyer state codes
- Validates GSTINs in real time
- Maintains HSN code library per industry (pharmacy, restaurant, hotel, etc.)
- Generates GSTR-1-ready data exports
- Handles e-invoicing for eligible businesses
- Supports credit notes, debit notes, and advances with correct GST treatment
Start with the free plan and get GST-compliant billing from your very first invoice — no accountant needed for the basics.
Summary
GST billing doesn't have to be complicated. The key is having software that understands Indian tax law and handles the rules automatically. Focus on running your business; let GoClixy handle the compliance.