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GST invoice format: what a tax invoice must show, and how to make one in your browser

By the Thryve team · updated 17 October 2026 · 7 min read

A GST invoice is an ordinary invoice with a few fields the rules insist on: your GSTIN, a serial number that runs in order, the HSN or SAC code of what you sold, the tax split into CGST and SGST (or IGST across states) and the place of supply. Get those right and any clean layout will do. Here is the list, then how to fill it in with Thryve Invoice, which runs in your browser and keeps your documents on your device.

What a tax invoice must contain

The CGST Rules list the particulars of a tax invoice. In plain terms, for a registered supplier they are:

  • Your name, address and GSTIN.
  • A consecutive serial number, unique for the financial year, up to 16 characters, which can include letters, numbers, a hyphen or a slash (for example TH/2026-27/0041).
  • The date of issue.
  • The recipient’s name, address and GSTIN if they are registered; for an unregistered recipient and a value of ₹50,000 or more, their name, address and the state.
  • The HSN code for goods or the SAC code for services. How many digits depends on your turnover; most small businesses use four or six.
  • A description of the goods or services, the quantity and unit for goods, and the total value.
  • The taxable value after any discount.
  • The rate and amount of tax: CGST and SGST (or UTGST) for a sale within your state; IGST for a sale to another state.
  • The place of supply with the state name, for an interstate sale.
  • Whether tax is payable on reverse charge.
  • A signature or digital signature of the supplier or an authorised person.

CGST and SGST, or IGST?

Same state as the buyer: split the rate in two, for example 9% CGST and 9% SGST for an 18% item. Another state: one line of 18% IGST. The total tax is the same; only the split changes. Union territories use UTGST instead of SGST.

If you are registered under the composition scheme, you issue a bill of supply instead and do not show tax at all; the bill must say “composition taxable person, not eligible to collect tax on supplies”.

Make it in Thryve Invoice

  1. Open Thryve Invoice and start a new invoice. Set the currency to INR.

  2. Under your details, fill in the name, address and put your GSTIN in the Tax / GST / VAT ID field. Add a custom field for State and state code if you want them shown.

  3. Do the same for the client, with their GSTIN. Add a custom field named Place of supply for interstate sales.

  4. Set the prefix and serial number so invoices run in order through the financial year, for example prefix TH/2026-27/ and number 0041. The next invoice continues the sequence.

  5. Add each item with its HSN or SAC code at the start of the description, the quantity and the rate.

  6. Add the tax as adjustments: two percentage lines named CGST 9% and SGST 9%, or one line named IGST 18%. A discount goes in as its own line before the tax.

  7. Put “Tax payable on reverse charge: No” and your bank details in the payment details or terms, upload your signature image, and export the PDF.

What Thryve Invoice does not do

  • It does not generate an e-invoice (IRN and QR code). E-invoicing is required above a turnover threshold and is done through the government portal or software connected to it; you can still prepare the invoice here and report it there.
  • It does not file returns or calculate your liability. It makes the document.
  • It does not know the HSN or SAC codes; look them up once for the things you sell and keep them in your item descriptions.

Questions, answered

Can I show CGST and SGST as separate lines?
Yes. Add two percentage adjustments named CGST and SGST with half the rate each. For an interstate sale, add one IGST line instead.
Where does the HSN or SAC code go?
In the item description, for example “998314 · Website design”. There is no separate HSN column, but the code appears on every line and in the PDF.
Are my invoices stored on a server?
No. Documents are saved in your browser on this device and exported as PDFs. Nothing is uploaded, which also means you should keep your own backups of the PDFs.
Is Thryve Invoice free?
Yes, with a free allowance of exports per month. Thryve Pro, a one-time payment, removes the allowance across every Thryve web app.

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