GST guide
GST invoice format: every field a tax invoice needs (with example)
A GST tax invoice is issued under Section 31 of the CGST Act and must carry the particulars listed in Rule 46 of the CGST Rules. Below they are marked on an example invoice, then laid out as a checklist, with how CGST, SGST and IGST are shown, numbering and rounding, and the extra details needed for unregistered customers.
Last reviewed: · CA review: pending
Who can issue a GST tax invoice
Only a GST-registered supplier can issue a tax invoice and charge GST. If you are not registered, you cannot charge GST or call your bill a tax invoice. Registered suppliers under the composition scheme issue a Bill of Supply instead (Rule 49), which never shows GST.
The rest of this page covers the ordinary tax invoice a regular GST-registered service business sends to its clients in India.
The format, on an example
A Mumbai design studio billing a Pune client: both in Maharashtra, so GST at 18% is split into CGST 9% and SGST 9%. Each number marks one of the particulars Rule 46 requires.
What each number means
1. Supplier name, address and GSTIN · Rule 46(a)
Your legal or trade name, your registered address and your 15-character GSTIN.
2. Invoice number · Rule 46(b)
Consecutive, unique for the financial year, up to 16 characters: letters, numbers, - and /.
3. Date of issue · Rule 46(c)
The date you issue the invoice.
4. Recipient name, address and GSTIN · Rule 46(d)
Your client’s GSTIN if they are registered. Unregistered clients: see the ₹50,000 rule below.
5. Place of supply · Rule 46(n)
State name and code. Required for inter-state supplies; Generate Invoice Online always prints it.
6. HSN / SAC code · Rule 46(g)
SAC for services, HSN for goods. Generate Invoice Online asks for one on every line.
7. Description · Rule 46(h)
What you supplied, in plain words.
8. Quantity · Rule 46(i)
Required for goods, with a unit. For services it isn’t mandatory, but hours, days or “1” make the invoice clearer.
9. Total and taxable value · Rule 46(j), (k)
Value of the supply, and the taxable value after any discount.
10. Tax rate and tax amount · Rule 46(l), (m)
Rate and amount for each tax: CGST + SGST (or UTGST) within a state, IGST across states.
11. Reverse charge · Rule 46(p)
Whether tax is payable on reverse charge. Generate Invoice Online prints “No” because reverse charge isn’t supported.
12. Signature · Rule 46(q)
Signature or digital signature of you or your authorised representative.
Amount in words isn’t listed in Rule 46, but most clients expect it and Generate Invoice Online adds it automatically. Rule references follow the current lettering of Rule 46 (clause (f) covers unregistered customers below ₹50,000 who ask for their details to be recorded).
Checklist: mandatory fields on a tax invoice
Every particular in Rule 46, and what Generate Invoice Online does with it. “Checked” means the editor flags the problem next to the field before you download.
| Field | Rule 46 | In Generate Invoice Online |
|---|---|---|
| Supplier name, address and GSTINRule 46(a) | Checked Name, address and city required; GSTIN format, checksum, and state code against your address. | |
| Invoice numberRule 46(b) | Checked Required, at most 16 characters, only letters, numbers, - and /. You keep it unique for the year. | |
| Date of issueRule 46(c) | Checked Required and must be a real date. | |
| Recipient name, address and GSTIN (if registered)Rule 46(d) | Checked Name required; a registered client’s address, city and GSTIN are required and the GSTIN is checked like yours. | |
| Unregistered recipient, ₹50,000 or more: address, delivery address, state name and codeRule 46(e) | Checked When the customer is unregistered and the taxable value is ₹50,000 or more, their address, city and state are required (printed with the state code). Add a “Ship to” address if delivery is elsewhere. | |
| HSN code (goods) or SAC (services)Rule 46(g) | Checked Required on every line. | |
| Description of goods or servicesRule 46(h) | Checked Required on every line. Write what you actually supplied. | |
| Quantity and unit (goods)Rule 46(i) | Printed Quantity on every line, with a standard unit code. | |
| Total value and taxable value after discountRule 46(j), (k) | Calculated Line discounts are applied before tax. | |
| Rate of taxRule 46(l) | Checked 5%, 18% or 40%; 12% and 28% get a warning after 22 Sep 2025; 0% is blocked. | |
| Amount of tax: CGST, SGST/UTGST or IGSTRule 46(m) | Calculated Split from your state and the place of supply. | |
| Place of supply, with state name (inter-state)Rule 46(n) | Checked Required on every invoice, printed with its state code. | |
| Delivery address, if different from place of supplyRule 46(o) | You confirm Add an optional “Ship to” address when it applies. | |
| Whether tax is payable on reverse chargeRule 46(p) | Printed Printed as “No”. Reverse-charge invoices aren’t supported. | |
| Signature or digital signatureRule 46(q) | You confirm An Authorised Signatory line is printed; you sign. | |
| QR code with IRN (e-invoicing taxpayers)Rule 46(r) | Not supported Generate Invoice Online does not generate e-invoices or IRNs. |
CGST + SGST or IGST: how tax is shown
The split depends on two things: the state you supply from and the place of supply.
- Same state (intra-state): charge CGST and SGST, each at half the GST rate. In Union Territories without a legislature (Chandigarh, Ladakh, Lakshadweep, Andaman and Nicobar Islands, and Dadra and Nagar Haveli and Daman and Diu), it is CGST + UTGST instead.
- Different state (inter-state): charge IGST at the full rate.
| ₹1,00,000 at 18% | Intra-state | Inter-state |
|---|---|---|
| CGST 9% | ₹ 9,000.00 | - |
| SGST 9% | ₹ 9,000.00 | - |
| IGST 18% | - | ₹ 18,000.00 |
| Invoice total | ₹ 1,18,000.00 | ₹ 1,18,000.00 |
Working out the place of supply for services
For most services between an Indian supplier and an Indian client, Section 12(2) of the IGST Act sets the place of supply as:
- the client’s location, if the client is GST-registered;
- the client’s address on record, if they are unregistered, or your own location if you have no address for them.
Some services follow different rules (Sections 12(3)–12(14)): services related to immovable property, events and admissions, training and performance, transport, telecom, banking and insurance, among others. Generate Invoice Online does not decide the place of supply for you. You choose it, and the editor applies CGST + SGST or IGST and shows why. If your service falls into one of the special categories, confirm the place of supply with your CA.
Invoice numbering rules
Rule 46(b) asks for a consecutive serial number that:
- is unique for the financial year (April to March);
- is at most 16 characters long;
- uses only letters, numbers, hyphens (-) and slashes (/);
- can run in one or more series, for example one per branch or business line.
A simple pattern is prefix + financial year + sequence, like INV/2026-27/001 (15 characters). Generate Invoice Online blocks numbers that are too long or use other characters, and suggests the next number in a financial-year series on your device. It can’t see invoices you made elsewhere, so keeping numbers unique is up to you.
Rounding
Generate Invoice Online calculates tax line by line to the paisa (half-up), and works out CGST and SGST separately, so the two halves always match. You can choose to round the grand total to the nearest rupee; the adjustment then appears as its own “Round off” line so the arithmetic stays visible.
Section 170 of the CGST Act rounds tax and other amounts payable under the Act to the nearest rupee (50 paise and above rounds up). Ask your CA how your returns and accounts treat invoice-level rounding if you’re unsure.
Unregistered customers: the ₹50,000 rule
You can issue a tax invoice to a customer who isn’t GST-registered. Leave their GSTIN out. What else must appear depends on the value:
- Taxable value of ₹50,000 or more (Rule 46(e)): the customer’s name and address, the delivery address, and the name of the state with its code.
- Below ₹50,000 (Rule 46(f)): the same details only if the customer asks for them to be recorded.
In Generate Invoice Online, choose “Unregistered” for the customer. Once the taxable value (before GST) reaches ₹50,000, the editor asks for their address, city and state and won’t create the PDF without them. Add a “Ship to” address if delivery is somewhere else.
How many HSN/SAC digits
Notification 78/2020-Central Tax sets the minimum number of HSN digits on a tax invoice from 1 April 2021, based on your aggregate turnover in the previous financial year:
- Up to ₹5 crore: 4 digits, and you may leave the code out on invoices to unregistered customers.
- Above ₹5 crore: 6 digits.
Generate Invoice Online is stricter: it asks for a code on every line and suggests common 6-digit SAC codes for services. It doesn’t tell you the GST rate for a code, so check that against the current rate notification.
When to issue the invoice
For services, Rule 47 of the CGST Rules requires the tax invoice within 30 days of the date of supply (45 days for banks, insurers and other financial institutions). The editor doesn’t check this. Use the optional supply date if it helps your client.
What Generate Invoice Online checks, and what you must confirm
Checked automatically
- GSTIN format, check digit and state code for you and for registered clients
- Invoice number present, at most 16 characters, allowed characters only
- Place of supply chosen, and CGST + SGST (or UTGST) vs IGST applied from it
- HSN/SAC on every line
- GST rate valid for the invoice date, including the rate changes effective 22 September 2025
- Supplier registered under the regular scheme (composition dealers are pointed to a Bill of Supply)
- Address and state for unregistered customers when the taxable value is ₹50,000 or more
- Totals, discounts, tax by rate and amount in words, calculated exactly
You must confirm
- The right SAC/HSN code and GST rate for what you supplied
- The place of supply, especially for the special services listed above
- That each invoice number is unique in the financial year
- A separate delivery (“Ship to”) address when goods or services are delivered elsewhere
- Signing the invoice (or using a digital signature)
- Whether e-invoicing applies to you. Businesses whose aggregate turnover has exceeded ₹5 crore in any financial year since 2017-18 must report B2B invoices to the Invoice Registration Portal and get an IRN. Generate Invoice Online cannot do this. Use an IRP-integrated solution if you’re covered.
- Reverse charge, exports, cess and supplies to SEZs are not supported here. See the FAQ.
Want to see the format filled in end to end? Look at the sample GST invoices, including one with IGST.
Sources
Primary GST law and notifications, plus reputable secondary references where marked. Rules change, so check the current text before relying on any single page.
- CGST Rules 2017, Rule 46: Tax invoice · CBIC tax information portal
- CGST Rules, Chapter VI: Tax invoice, credit and debit notes (Rules 46–49) · CBIC GST portal
- Background material on GST, Chapter 7: Tax invoice, credit and debit notes (current clause lettering of Rule 46) · ICAI Indirect Taxes Committee (secondary source)
- CGST Act 2017, Sections 2(6), 31, 32 and 170 (CBIC consolidated text, amended to 30 Sep 2020) · CBIC GST portal
- Sectoral FAQs on GST (an unregistered person cannot issue a tax invoice) · CBIC GST portal
- IGST Act 2017 (as enacted), Section 12: Place of supply of services (supplier and recipient in India); Section 16: zero-rated supply · GST Council
- Notification No. 78/2020-Central Tax: HSN digits on tax invoices from 1 April 2021 · GST Council
- Notification No. 10/2023-Central Tax: e-invoicing threshold lowered to ₹5 crore from 1 August 2023 · GST Council
- GSTN advisory: 30-day time limit for reporting e-invoices (AATO ₹10 crore and above, from 1 April 2025) · Maharashtra GST Department (GSTN advisory copy)
- Notifications 9/2025 and 15/2025-Central Tax (Rate), dated 17 Sep 2025, effective 22 Sep 2025 (summary) · StudyCafe (secondary source)
General information, not tax advice. Generate Invoice Online helps you format invoices and checks for common GST-related issues; it is not a tax, legal or accounting advisor. GST rules change, so confirm anything unusual with your CA.