GST Invoice Format

What a GST invoice must contain

Missing any of these can hold up your client's input tax credit, which is when they ask you to reissue and the payment slips another week.

• Your business name, address and GSTIN
• The buyer's name, address and GSTIN if they are registered
• A unique invoice number, continuous through the financial year, up to 16 characters
• The date of issue
• HSN code for goods, or SAC code for services
• Description, quantity, unit and rate for each line
• Taxable value, then tax rate and tax amount shown separately
• Total in figures, and the amount in words
• Place of supply, if it differs from the buyer address
• Signature or digital signature of the supplier

CGST and SGST, or IGST?

It depends on the place of supply — where your client is, not where you are. Within your own state, split the rate in half: 18% becomes 9% CGST plus 9% SGST. Outside your state, the full 18% goes on one line as IGST. The builder has a single checkbox for inter-state supply, so you cannot forget to switch it.

Invoice numbering rules

The series must be continuous through the financial year, unique, and no longer than 16 characters. Only letters, numbers, the forward slash and the hyphen are allowed. A format like ANV/25-26/001 works well because the year is visible. If you cancel an invoice, keep the cancelled entry or raise a credit note — do not skip the number.

Common mistakes

• Resetting the numbering in the middle of the financial year
• Charging IGST on a same-state supply, or the other way round
• Leaving out the amount in words
• No HSN or SAC code where turnover makes it mandatory
• Writing "payment on receipt" instead of a real due date

Questions

This page is general information, not tax or legal advice. Rules change and what applies depends on your business — confirm anything important with your CA.