The complete GST invoice format guide (with template)

Every GST-compliant tax invoice in India has to follow Rule 46 of the CGST Rules, 2017. The rule is short. Whether you're a freelancer billing a single client or running a company billing dozens — same format applies. Get one field wrong and an auditor can disqualify the invoice (and your client's input tax credit on it).

This guide walks through every mandatory field, what it means, when you need it, and what most people get wrong.

What Rule 46 actually requires

Rule 46 mandates the following on every tax invoice. Missing any of these is non-compliance:

1. Name, address, GSTIN of the supplier — your details
2. Invoice number — unique, sequential, max 16 characters (numbers, letters, hyphens, slashes only). One series per financial year.
3. Date of issue
4. Name, address, GSTIN/UIN of the recipient (if registered)
5. Address of delivery with state code (if different from the billing address)
6. HSN or SAC code for goods/services
7. Description of goods/services
8. Quantity (and unit, for goods)
9. Total value
10. Taxable value (after any discount)
11. Rate of GST (CGST, SGST/UTGST, IGST and Cess separately)
12. Amount of tax charged (each tax separately)
13. Place of supply + state name and code
14. Whether tax is payable on reverse charge
15. Signature/digital signature of the supplier

Walk-through: a typical B2B services invoice

Say you're a freelance developer billing a Mumbai company ₹50,000 plus 18% GST.

Header block (you)

• Your name + business name
• Full address with state + PIN
• Your GSTIN (15 digits)
• Optional: PAN if your business isn't a sole prop

Customer block (them)

• Company name
• Full address with state + PIN
• Their GSTIN (15 digits) — critical for B2B
• Place of supply — for services, this is usually the recipient's state

Invoice meta

• Invoice number — something like INV-2026-0042. One series, ascending. Don't skip numbers.
• Invoice date
• Due date — not technically required, but customers expect it

Line items

For each service: description, SAC code, taxable value, GST rate, GST amount. For development work in India, SAC 998314 (information technology consulting and support services) is common.

Tax breakdown

This is where place of supply matters:

• Same state (intra-state) — split into CGST 9% + SGST 9% = 18% total
• Different state (inter-state) — IGST 18% as a single line
• Export/SEZ — 0% (under LUT) or IGST 18% (without LUT)

Totals

• Sub-total (taxable value)
• Each tax line (CGST/SGST/IGST/Cess)
• Total amount in figures
• Total amount in words— using Indian numbering system (lakh/crore), prefixed with "Indian Rupees"

Footer

• Bank details for payment (account, IFSC, SWIFT for overseas)
• Terms (payment terms, late fee, etc.)
• Signature (physical or digital)
• For reverse charge cases: clear "Tax is payable on reverse charge basis" statement

Common mistakes (and what auditors will catch)

• Skipping the invoice number sequence. If you go INV-001 → INV-002 → INV-004, an auditor will ask where INV-003 went. Cancellations should be marked, not skipped.
• Wrong place of supply.Place of supply for services to a registered customer is the recipient's state. Many freelancers default to their own state — making intra-state invoices look inter-state and vice versa. Both tax-classifications wrong.
• Missing HSN/SAC.Even if you're below the turnover threshold for mandatory HSN reporting, it's safer to include it. Costs nothing.
• Wrong tax type for inter-state. Charging CGST+SGST on an inter-state supply (or vice versa) is the most common GST error for new freelancers. Place of supply ≠ your state means IGST.
• Amount in words wrong.₹1,00,000 in words is "Indian Rupees One Lakh Only" — not "One Hundred Thousand" (US-style). Indian numbering uses lakh and crore.
• No reverse charge mentionwhen applicable. If your customer is liable for tax under RCM (reverse charge mechanism), your invoice must state "Tax payable on reverse charge."

B2B vs B2C invoices

B2B— recipient has a GSTIN. They'll claim input tax credit on this invoice. Get every field right. Their GSTIN goes on your GSTR-1.

B2C— consumer. No GSTIN. For invoices < ₹50,000, consumer details are optional. For ≥ ₹50,000 you need name + address. Place of supply still required.

Export invoices

Different rules apply for exports. Recipient has no GSTIN, place of supply is code 96 (Other Country), tax is either 0% (LUT) or 18% IGST (without LUT). The invoice must contain an explicit export declaration statement.

We wrote a full guide on this: see How to invoice US clients from India.

Penalty for non-compliance

Under Section 122(1) of the CGST Act, issuing an incorrect invoice can attract a penalty of ₹10,000 or the tax evaded (whichever is higher). Not catastrophic on a single invoice, but at scale + interest on unpaid GST, it adds up.

More common consequence: your customer's input tax credit claim gets disallowed in their audit. They'll then come back to you to fix it. Annoying.

Sample compliant invoice (text version)

Doing this in HootZen

We built HootZen so you don't have to remember any of this. Pick the customer (HootZen detects place of supply from their address), add line items (HSN/SAC autocomplete), the right tax type fills in automatically — CGST+SGST for same-state, IGST for inter-state, 0% for exports with LUT. Amount-in-words generates in proper Indian numbering. Reverse charge label drops in when applicable.

You shouldn't have to be a GST expert to send a compliant invoice. That's the whole point.