Mandatory fields on a GST tax invoice
Under GST rules, a tax invoice must carry the following information. A good free GST invoice generator includes these fields by default.
- The words "Tax Invoice" clearly displayed
- Your registered business name, address and GSTIN
- The recipient’s name, address and GSTIN (for B2B sales)
- A unique, consecutive invoice number and the invoice date
- HSN code for goods or SAC code for services
- Description, quantity and value of each item or service
- Total taxable value and the applicable GST rate
- The CGST/SGST or IGST breakup and the total invoice value
- Place of supply, and the signature of the supplier
CGST and SGST vs IGST
If the place of supply is in the same state as your registration, GST splits into CGST plus SGST (each half of the rate). If the sale is interstate, a single IGST at the full rate applies. Getting this split wrong is one of the most common invoicing mistakes — an automated generator applies the correct treatment based on state.
Common GST invoice mistakes to avoid
- Skipping HSN/SAC codes or using the wrong classification
- Reusing or skipping invoice numbers, breaking the sequence
- Charging CGST/SGST on an interstate sale instead of IGST
- Not updating a changed GSTIN on your invoices
- Omitting the place of supply on services
How to generate a free GST invoice online
Add your business and GSTIN once, enter your buyer and line items, and let the generator compute tax and build the summary. ProfessionalBill’s free GST invoice templates already include GSTIN, HSN/SAC, place of supply and automatic CGST/SGST/IGST — so your invoice is compliant from the first bill.