GST Invoice Format 2026: Mandatory Fields Under Rule 46 (Free Template)

Sending an invoice to a client should be the happiest moment for a small business owner. But under the Indian tax system, a non-compliant invoice can quickly turn into a nightmare. If your bill lacks the mandatory fields dictated by the government, your buyer will be denied their Input Tax Credit (ITC), and you could face severe penalties during a tax audit.

As we move through 2026, compliance rules have only become stricter. This guide will walk you through the exact GST invoice format required to keep you out of trouble, so you can focus on getting paid.

The Rule 46 GST Invoice Requirements

The government doesn’t care what color your logo is or what font you use. They only care that your bill contains specific data points. These rules are outlined in Rule 46 of the CGST Rules.

To create a 100% compliant tax invoice, you must include:

1. Title: The document must prominently display the words “Tax Invoice.”
2. Supplier Details: Your business name, address, and GSTIN.
3. Buyer Details: The customer’s name, address, and GSTIN (if registered).
4. Invoice Number: A unique, consecutive alphanumeric number (max 16 characters) for that financial year.
5. Invoice Date: The exact date the invoice was issued.
6. HSN or SAC Code: Minimum 4 digits for turnover up to ₹5 crore, and 6 digits for turnover above ₹5 crore.
7. Item Details: Description of goods or services, quantity, and unit metric (e.g., kg, pcs).
8. Taxable Value: The base price before tax or discounts.
9. Tax Rate: The applicable GST 2.0 slab (0%, 5%, 18%, or 40%).
10. Tax Amount: Clearly split into CGST, SGST, or IGST.
11. Place of Supply: Mandatory if it is an inter-state sale.
12. Signature: Physical or digital signature of the authorized supplier.

If you are missing even one of these mandatory fields in tax invoice documents, the bill is legally invalid.

👉 Try it yourself: Don’t risk missing a mandatory field. Use our GST Invoice Generator to create perfectly compliant, professional PDF invoices instantly in your browser.

B2B vs B2C Invoice: What is the Difference?

The formatting rules shift slightly depending on who you are selling to.

B2B Invoices (Business to Business)

When you sell to another GST-registered business, they will want to claim ITC. Therefore, a B2B invoice must include the buyer’s GSTIN. Before issuing a high-value B2B invoice, you should always run the buyer’s details through a GSTIN Validator to ensure their registration is active and legitimate.

B2C Invoices (Business to Consumer)

When selling to an unregistered end-consumer, you do not need their GSTIN.

• For B2C sales under ₹2.5 lakh, you only need to show the state name if it’s an inter-state supply.
• For B2C sales over ₹2.5 lakh (inter-state), you must include the buyer’s full name and address along with the state code.

The E-Invoicing Limit 2026

If you think a standard PDF invoice is enough, you need to check your turnover. The government has aggressively pushed e-invoicing to curb tax evasion.

As of 2026, the e-invoicing limit 2026 requires any business with an aggregate annual turnover exceeding ₹5 Crores in any preceding financial year (from 2017-18 onwards) to generate e-invoices for all B2B transactions.

This means you must upload your invoice data to the Invoice Registration Portal (IRP). The IRP will return an Invoice Reference Number (IRN) and a QR code, which must be printed on your final bill. If you cross this threshold and issue a standard invoice without a QR code, it is treated as if no invoice was issued at all.

How to Calculate Taxes on the Invoice

When formatting your invoice, the math must be perfect. If you are selling an item at the new standard 18% slab, you must calculate the exact tax amount on the base taxable value.

For an intra-state sale (within your state), you must split the 18% into two separate line items:

• CGST @ 9%
• SGST @ 9%

If it is an inter-state sale, you show a single line item:

• IGST @ 18%

If math isn’t your strong suit, never guess. Use a dedicated GST Calculator to get the exact base, CGST, and SGST split before typing it into your invoice template.

Frequently Asked Questions

Is a signature mandatory on a GST invoice? Yes. A tax invoice must be signed by the authorized representative. This can be a physical wet-ink signature or a legally valid digital signature.

Can I use the same invoice number format every year? You must restart your invoice numbering sequence at the beginning of every financial year (April 1st) to ensure uniqueness.

What is the difference between a Bill of Supply and a Tax Invoice? A Tax Invoice is issued when you charge GST. A Bill of Supply is issued by composition scheme dealers or for exempt goods (0% GST), where no tax is charged to the buyer.

Do I need an HSN code for a B2C invoice? If your aggregate turnover in the preceding financial year was more than ₹5 crores, HSN codes are mandatory for B2C invoices as well.

Can I make an invoice in Excel or Word? Yes, it is perfectly legal to create an invoice in Excel, Word, or any offline tool, as long as it contains all the mandatory fields required under Rule 46.

Generate Flawless Invoices Today

Creating a compliant bill shouldn’t require an expensive software subscription. As long as you follow the rule 46 gst invoice guidelines, your bills will pass any audit.

(Read next: How to Verify a GST Number Online)