Key takeaways
- A GST tax invoice must carry the fields listed in Rule 46 of the CGST Rules, including GSTIN, a unique serial number, HSN/SAC codes, taxable value, rate and tax amount.
- Sales inside your state show CGST and SGST in equal halves; sales to another state show IGST.
- Composition dealers and sellers of exempt goods issue a bill of supply, not a tax invoice.
- An ordinary PDF tax invoice is not an e-invoice. Businesses above the e-invoicing threshold must also get an IRN.
A GST invoice is more than a bill. It is the document your customer uses to claim input tax credit, and the record the tax department checks against your returns. Getting the format right saves you from rejected credits, awkward phone calls and notices later.
This guide walks through every field, explains which document to use when, and shows a sample layout you can reproduce in the free GST invoice generator.
The fields a tax invoice must show
The contents are set by Rule 46 of the CGST Rules. In plain words, a tax invoice needs:
- Your name, address and GSTIN.
- A serial number of up to 16 characters (letters, numbers, hyphen or slash), consecutive and unique for the financial year. Many businesses use a prefix such as
INV/26-27/0001. - Date of issue.
- Customer’s name and address, and their GSTIN if they are registered.
- Place of supply (state name and code) when the customer is unregistered and the invoice is ₹50,000 or more, and for every inter-state sale in practice.
- Delivery address if it differs from the place of supply.
- HSN code for goods or SAC code for services, with a description.
- Quantity and unit for goods.
- Total value, discount and taxable value.
- Tax rate and tax amount, split into CGST and SGST/UTGST, or shown as IGST.
- Whether tax is payable on reverse charge.
- Signature or digital signature of the supplier or an authorised person.
How many HSN digits you print depends on your aggregate turnover in the previous year. Check the current notification on the GST portal for your case.
CGST + SGST or IGST?
The split depends on where the supply happens:
| Situation | Tax shown on invoice | Example on ₹10,000 at 18% |
|---|---|---|
| Seller and place of supply in the same state | CGST + SGST (or UTGST) | ₹900 + ₹900 |
| Place of supply in a different state | IGST | ₹1,800 |
| Export or supply to an SEZ | IGST or zero-rated under LUT | Depends on LUT |
The customer pays the same total either way. What changes is which government receives the money, so a wrong split is a real error even when the total is right.
Tax invoice, bill of supply or something else?
- Tax invoice: the normal document when you charge GST.
- Bill of supply: used by composition taxpayers and for exempt goods or services. It shows no tax.
- Proforma invoice or quotation: a price offer before the sale. It is not a tax document and does not support input tax credit.
- Credit note / debit note: to reduce or increase the value of an invoice already issued, for example after a return or a price correction.
- Receipt voucher: issued when you receive an advance.
The free invoice generator offers tax invoice, plain invoice, bill of supply, proforma and quotation layouts, so you can pick the right one before filling in the details.
A sample layout that works
A clean invoice reads top to bottom in the order a customer checks it:
- Header: your logo, name, address, GSTIN, and the words Tax Invoice.
- Invoice details: number, date, due date, place of supply, reverse charge (Yes/No).
- Bill to / Ship to: customer details side by side.
- Items table: description, HSN/SAC, quantity, unit, rate, discount, taxable value, GST rate, tax.
- Totals: taxable value, CGST, SGST or IGST, round-off, grand total, and the amount in words.
- Payment: bank details and a UPI QR code with the amount filled in.
- Footer: terms, and the signature block “For
– Authorised signatory”.
Common mistakes
- Reusing or skipping numbers. Numbers must be consecutive within the financial year. Start a new series on 1 April.
- Charging IGST on a local sale (or the reverse). The customer’s credit can be denied.
- Missing the customer’s GSTIN on a B2B invoice, which blocks their credit.
- Wrong rates after a rate change. Since 22 September 2025 most items moved to the 5% and 18% slabs, with 40% for some luxury and sin goods. Check the rate for each HSN code.
- Treating a PDF as an e-invoice. If your turnover is above the e-invoicing limit, you must also report the invoice to the Invoice Registration Portal to get an IRN and QR code.
Make one now
Open the GST invoice generator, fill in the fields above, and save it as a PDF. Nothing you type is uploaded. If you invoice every day, the free desktop app CrizaVoise keeps your customers, products and invoice numbers for you and works offline.
This guide explains the general format. It is not tax advice; a chartered accountant can confirm what applies to your business.
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