Under India’s Goods and Services Tax (GST), a registered supplier must issue a tax invoice with specific particulars set out in the CGST Rules (Rule 46). Getting it right matters: your customer’s input tax credit depends on it, and in-scope businesses must also register invoices on the e-invoicing system. This guide explains the required fields and the most common rules.
GST rules, rates and thresholds are amended regularly through notifications and circulars. This guide summarises the general position as of October 2026 and is not tax or legal advice. Confirm with a GST practitioner or the official GST portal.
Who must issue a GST tax invoice?
Every GST-registered person making a taxable supply. Registration is generally required once aggregate turnover exceeds ₹40 lakh for suppliers of goods or ₹20 lakh for services (lower limits apply in some special-category states), and in certain cases regardless of turnover — for example, many inter-state suppliers and e-commerce sellers.
- Registered under the composition scheme, or supplying only exempt goods/services? Issue a bill of supply instead — no GST charged.
- Not registered? You can’t charge GST or issue a tax invoice.
Mandatory contents of a tax invoice
| Field | Notes |
|---|---|
| Supplier’s name, address and GSTIN | 15-character GST identification number |
| Invoice number | Consecutive serial number, up to 16 characters (letters, digits, “-” and “/”), unique for the financial year |
| Date of issue | |
| Recipient’s name, address and GSTIN | If the recipient is registered |
| Recipient details for unregistered buyers | Name, address and delivery address with state name and code where the taxable value is ₹50,000 or more (and in other cases required by the rules) |
| HSN code (goods) or SAC (services) | Number of digits depends on turnover — see below |
| Description, quantity and unit | |
| Total value and taxable value | After discounts or abatements |
| Tax rate and amount | Separately for CGST, SGST/UTGST, IGST and cess, as applicable |
| Place of supply | With state name, for inter-state supplies |
| Delivery address | If different from place of supply |
| Reverse charge | Whether tax is payable on reverse charge |
| Signature | Physical or digital signature of the supplier or authorised representative |
HSN/SAC codes
Since April 2021, the minimum number of HSN digits on invoices depends on your aggregate turnover in the previous financial year:
| Turnover | HSN digits |
|---|---|
| Up to ₹5 crore | 4 digits (mandatory for B2B supplies; optional for B2C) |
| Above ₹5 crore | 6 digits for all supplies |
Services use SAC codes (commonly 6 digits, starting with 99).
CGST + SGST or IGST?
It depends on whether the supply is intra-state or inter-state (based on the supplier’s location and the place of supply):
| Supply | Tax charged | Example at 18% |
|---|---|---|
| Within the same state | CGST + SGST (or UTGST) | 9% + 9% |
| Between states (or to/from a SEZ) | IGST | 18% |
| Export | Zero-rated | IGST paid and refunded, or 0% under LUT |
Example — a Bengaluru designer billing a Karnataka client ₹50,000 at 18%: CGST ₹4,500 + SGST ₹4,500 = ₹59,000. The same invoice to a Mumbai client: IGST ₹9,000 = ₹59,000.
GST rates
Following the rate rationalisation that took effect in September 2025, the main GST slabs are 5% and 18%, with a 40% rate for certain luxury and “sin” goods, plus nil-rated items and special rates (e.g. for precious metals). Most professional services fall under 18%. Rates are notified per HSN/SAC code — always check the current rate for your specific goods or services.
Time limits for issuing invoices
- Goods: before or at the time of removal (dispatch) or delivery.
- Services: generally within 30 days of the supply (45 days for certain financial institutions).
- Continuous supplies and advance receipts have specific rules — advances on services generally require a receipt voucher.
Copies
For goods, the rules call for the invoice in triplicate (original for recipient, duplicate for transporter, triplicate for supplier); for services, duplicate. Under e-invoicing, the electronic record largely replaces this in practice.
E-invoicing (IRN)
Businesses whose aggregate turnover in any financial year since 2017-18 exceeded ₹5 crore must report B2B invoices (and credit/debit notes and exports) to the Invoice Registration Portal (IRP), which returns an Invoice Reference Number (IRN) and a signed QR code to print on the invoice. An in-scope invoice without an IRN is not treated as a valid tax invoice. Some sectors are exempt. Businesses above ₹10 crore AATO face a 30-day limit for reporting invoices to the IRP. See what is an e-invoice for the global picture.
Exports of services
Exports of services are zero-rated. Most small exporters furnish a Letter of Undertaking (LUT) and invoice without IGST, with the note “Supply meant for export under LUT without payment of IGST”, the LUT reference, and the foreign client’s details. Payment must generally be received in convertible foreign exchange (or INR where RBI permits). See invoicing international clients.
Sample layout (services, intra-state)
| Field | Example |
|---|---|
| Supplier | Kavya Rao Design, Indiranagar, Bengaluru, Karnataka · GSTIN 29XXXXX… |
| Invoice no. / date | KRD/2026-27/042 · 28 Oct 2026 |
| Recipient | Northwind Retail Pvt Ltd, Bengaluru · GSTIN 29YYYYY… |
| Place of supply | Karnataka (29) |
| Description | SAC | Taxable value | CGST 9% | SGST 9% | Total |
|---|---|---|---|---|---|
| Brand identity design | 998391 | ₹50,000 | ₹4,500 | ₹4,500 | ₹59,000 |
Tax payable on reverse charge: No. Authorised signatory. (GSTINs truncated; SAC code shown for illustration — verify the correct code.)
Checklist
- GSTINs of supplier and (if registered) recipient
- Unique serial number ≤16 characters for the financial year
- HSN/SAC with the required digits
- Taxable value and CGST/SGST or IGST split correctly
- Place of supply with state name and code
- Reverse charge indicator
- Signature (physical or digital)
- IRN and QR code if you’re in scope for e-invoicing
- LUT note for zero-rated exports
You can build an invoice with GST in the invoice generator — choose INR, and use the second-tax option for CGST + SGST. For in-scope e-invoices, you’ll still need to register them on the IRP through compliant software. See also our India invoice template page.