GST Invoice Format: 16 Mandatory Fields Every Indian Business Must Include

A GST tax invoice isn’t just a bill — it is the document your customer uses to claim input tax credit. If a mandatory detail is missing, their credit can be denied and you may face penalties. Here’s what Rule 46 of the CGST Rules requires.

The mandatory fields

1. Supplier’s name, address and GSTIN
2. Invoice number — consecutive, unique for the financial year, max 16 characters (letters, numbers, - and / allowed). Example: INV/26-27/0001.
3. Date of issue
4. Recipient’s name, address and GSTIN (if registered)
5. Recipient’s name, address, state and state code when the recipient is unregistered and the invoice value is ₹50,000 or more
6. HSN code for goods or SAC for services (4 digits up to ₹5 crore turnover, 6 digits above that)
7. Description of goods or services
8. Quantity and unit
9. Total value of supply
10. Taxable value after discounts
11. Rate of tax — CGST, SGST/UTGST, IGST and cess
12. Amount of tax for each head
13. Place of supply with state name — this decides CGST+SGST vs IGST
14. Delivery address if different from place of supply
15. Whether tax is payable on reverse charge
16. Signature or digital signature of the supplier or authorised person

CGST + SGST or IGST?

Supplier state	Place of supply	Tax charged
Maharashtra	Maharashtra	CGST 9% + SGST 9%
Maharashtra	Karnataka	IGST 18%

Common mistakes

• Restarting invoice numbers mid-year or skipping numbers
• Charging IGST on a local sale (or vice versa) — your customer’s ITC will mismatch
• Missing HSN codes
• Not mentioning place of supply for inter-state B2C sales

Composition dealers

If you’ve opted for the composition scheme you cannot charge GST. Issue a Bill of Supply with the line “Composition taxable person, not eligible to collect tax on supplies”.

DhandhaBook fills all of this automatically — numbering, HSN, place of supply, CGST/SGST/IGST and amount in words — so every invoice is compliant by default.