GST invoice requirements
Rule 46 of the Central GST Rules lists what a tax invoice must show. Use this checklist before you send an invoice.
By Aura Labs · Last reviewed September 2026
Mandatory fields
- Supplier's name, address and GSTIN
- A consecutive serial number, unique for the financial year, up to 16 characters
- Date of issue
- Recipient's name, address and GSTIN (if registered)
- Place of supply with state name and code, for interstate supplies
- HSN code for goods or SAC for services
- Description, quantity and unit of goods
- Total value and taxable value after discounts
- Rate and amount of tax: CGST, SGST/UTGST or IGST, and cess if any
- Whether tax is payable on reverse charge
- Signature or digital signature of the supplier
Common mistakes
- Charging CGST + SGST on a sale to another state (it should be IGST)
- Gaps or duplicates in invoice numbers
- Wrong or missing customer GSTIN, which stops them from claiming input tax credit
- Taxing the pre-discount value instead of the discounted taxable value
Where the rules change
Thresholds for HSN digits and e-invoicing are revised through notifications. Check the current position on the CBIC site or with your CA.
GST rates and rules change. Please verify current rules with official government sources or your CA before filing.
Frequently asked questions
Only when the customer is registered. For an unregistered customer, the name and address and place of supply are shown instead; for large B2C values the delivery address is also required.
Yes — a physical or digital signature of the supplier or authorised representative. Electronic invoices under e-invoicing follow their own rules.
You can't charge GST, so you issue a Bill of Supply rather than a tax invoice.
Official sources
A checklist built in
BillBook prompts for GSTIN, HSN/SAC and place of supply, and numbers invoices for you.
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