What is a GST Invoice?
A GST invoice is a legal document issued by a GST-registered supplier to a buyer. It details the goods or services provided, the applicable GST rate, and the total amount payable including taxes. Under India's Goods and Services Tax (GST) Act, every registered business must issue a compliant tax invoice for every sale.
Mandatory Fields on a GST Invoice
A valid GST tax invoice must include: (1) Name, address, and GSTIN of the supplier, (2) A unique invoice number, (3) Date of issue, (4) Name, address, and GSTIN of the recipient (for B2B), (5) Description of goods/services, (6) HSN/SAC code, (7) Quantity and unit of measure, (8) Taxable value, (9) GST rate (CGST + SGST for intra-state, or IGST for inter-state), (10) Total invoice amount in words.
How to Calculate CGST and SGST
For intra-state transactions (buyer and seller in same state), GST is split equally between Central GST (CGST) and State GST (SGST). For example, an item with 18% GST: CGST = 9% and SGST = 9%. Multiply the taxable value by each rate to get the tax amounts. InvoiceGPT calculates this automatically for every line item.
Step-by-Step: Create Your First GST Invoice
Step 1: Sign in to InvoiceGPT with your Google account. Step 2: Go to Settings and enter your business name, GSTIN, and address. Step 3: Click 'New Invoice'. Step 4: Add a client name (and their GSTIN for B2B). Step 5: Add line items — each with a description, quantity, rate, and GST percentage. Step 6: InvoiceGPT auto-calculates CGST, SGST, and the total. Step 7: Click Download PDF to get your ready-to-share GST invoice.
Common GST Invoice Mistakes to Avoid
The most common mistakes include: using wrong GST rates for items, forgetting to mention HSN codes (mandatory for businesses over ₹5 crore turnover), not mentioning the place of supply for interstate transactions, using the same invoice number twice, and not mentioning GSTIN for B2B transactions above ₹50,000.