01.The fields every GST tax invoice needs
Rule 46 of the CGST Rules sets out what a tax invoice must contain. In practice, a seller’s invoice should show the following:
| Field | What to write |
|---|---|
| Invoice number | Unique and in sequence within the financial year, up to 16 characters, e.g. INV/25-26/0042 |
| Invoice date | The date of issue |
| Your details | Legal or trade name, address and GSTIN |
| Buyer’s details | Name, address and GSTIN if registered; for unregistered buyers, name and address are also expected on larger invoices |
| Place of supply | The state where goods are delivered; decides CGST/SGST or IGST |
| Description, HSN, quantity | What was sold, its HSN code, units and quantity |
| Taxable value | Value after any discount, before GST |
| Tax rate and amount | CGST and SGST, or IGST, shown separately |
| Total | Invoice value, usually with the amount in words |
| Signature | Physical or digital signature of you or an authorised person |
02.CGST and SGST, or IGST?
The place of supply decides which tax you charge. If you and the buyer are in the same state, the GST is split equally into CGST and SGST. If the goods go to another state, the whole amount is IGST.
| Sale | Example at 5% GST on ₹1,000 (hypothetical) | Tax shown |
|---|---|---|
| Gujarat seller to Gujarat buyer | CGST 2.5% = ₹25, SGST 2.5% = ₹25 | ₹50 split in two |
| Gujarat seller to Maharashtra buyer | IGST 5% = ₹50 | ₹50 as one line |
The total is the same either way. Only the way it is reported changes, so a wrong split makes filing harder for both of you.
03.How many HSN digits to show
HSN codes classify goods. Since April 2021, the number of digits depends on your aggregate annual turnover in the previous year:
- Up to ₹5 crore: at least 4 digits on invoices to registered buyers (B2B); optional for B2C.
- Above ₹5 crore: at least 6 digits on all tax invoices.
For clothing, codes start with 61 for knitted garments and 62 for garments that are not knitted. See our guide to GST on clothes and HSN codes for common apparel codes.
04.Tax invoice, bill of supply or e-invoice?
- Tax invoice: issued by a GST-registered seller for a taxable sale.
- Bill of supply: issued for exempt goods or by a seller on the composition scheme, who cannot charge GST.
- E-invoice: businesses above the e-invoicing turnover limit (₹5 crore at the time of writing) must also register B2B invoices on the government Invoice Registration Portal to get an IRN and QR code.
05.Common invoice mistakes
- Reusing an invoice number, or restarting the sequence mid-year.
- Charging IGST on a sale within your own state, or CGST and SGST on an inter-state sale.
- Leaving out the buyer’s GSTIN on a B2B sale, which blocks their input tax credit.
- Showing a GST-inclusive price as the taxable value.
- Missing HSN codes on B2B invoices.
If you also need a payment QR on the invoice, make one with the free UPI QR code generator, and work out tax-inclusive prices with the GST calculator.
