GST Invoice Generator

How this calculator works

What makes an invoice GST-compliant

The Central Goods and Services Tax Rules, 2017 specify the minimum fields a tax invoice must carry. Your invoice is invalid for input tax credit if any of these are missing — your buyer's accountant will flag it and demand a corrected version.

The mandatory fields:

• Name, address and GSTIN of the supplier
• A consecutive serial number, unique within a financial year, up to 16 characters (alphanumeric and special characters allowed)
• Date of issue
• Name, address and GSTIN of the recipient (if registered)
• For B2C above ₹50,000: name, address and state of recipient even if unregistered
• HSN code for goods or SAC code for services
• Description of goods or services
• Quantity (for goods) and unit (sqft, kg, hour, etc.)
• Total value of supply
• Taxable value after any discount
• Rate of tax (CGST, SGST/UTGST, IGST and cess separately)
• Amount of tax charged
• Place of supply along with the state name (and code) — critical for inter-state determination
• Address of delivery if different from place of supply
• Whether tax is payable on reverse charge
• Signature or digital signature of supplier or authorised representative

Your serial number scheme matters more than people realise. The rules say "unique within a financial year". You can use any prefix you like (INV/26-27/001, TAX/2604/0001, anything), but you cannot repeat a number within a year, and you should not skip numbers. Auditors look for gaps. If you cancel an invoice, mark it cancelled and keep the record — don't reuse the number.

Place of supply — the field most people get wrong

Place of supply determines whether the transaction is intra-state (CGST + SGST) or inter-state (IGST). For goods, it's usually the location where movement of goods terminates for delivery to the recipient. For services, the rules vary by service type — and this is where it gets tricky.

For most services to a registered recipient, place of supply is the recipient's registered location. So a freelance designer in Bengaluru working for a Mumbai-registered company is making an inter-state supply. IGST applies, not CGST plus SGST. Many small consultants get this wrong, charge SGST plus CGST, and have to issue credit notes and reissue with IGST when the buyer's accounts team challenges it.

For services to unregistered recipients, place of supply is generally the recipient's address on record, or if unavailable, the supplier's location. Specific service categories (telecom, banking, transportation, immovable property, accommodation, training, events) have their own place-of-supply rules under Sections 12 and 13 of the IGST Act.

HSN and SAC codes

HSN (Harmonised System of Nomenclature) codes are 4, 6, or 8-digit codes for goods. SAC (Services Accounting Code) codes are 6-digit codes for services. The number of digits you must report depends on your turnover:

• Up to ₹5 crore turnover: 4-digit HSN/SAC
• Above ₹5 crore: 6-digit HSN/SAC
• Exports: 8-digit HSN/SAC mandatory

Common SAC codes worth memorising if you're a freelancer or service business: 998313 (information technology consulting), 998311 (management consulting), 998314 (information technology design and development), 998361 (advertising services), 998314 (software development), 998596 (event management), 998339 (engineering consulting). The full list runs to several hundred codes.

Amount in words

Rule 46 of the CGST Rules requires the total invoice amount to be shown in figures and words. The conversion uses the Indian numbering system — lakh and crore, not million and billion. ₹2,36,000 reads as "Rupees Two Lakh Thirty-Six Thousand Only". Western numbering ("Two Hundred Thirty-Six Thousand") is technically incorrect on an Indian invoice.

E-invoicing — when it kicks in

Businesses with aggregate turnover above ₹5 crore in any financial year since 2017-18 must generate e-invoices through the official Invoice Registration Portal (IRP). The IRP issues an Invoice Reference Number (IRN) and a QR code that must be printed on the invoice. Your invoice is invalid without the IRN once you cross the threshold. Below ₹5 crore, e-invoicing is optional but increasingly common as buyers prefer suppliers who can issue e-invoices directly.

What this tool does

The generator builds a clean A4 PDF in your browser using jsPDF. Your logo is embedded as base64 within the PDF (it's never uploaded anywhere). Line items, GST split, and totals are computed client-side. The PDF you download is yours alone — no server stores it, no analytics watch what you're billing.

Worked example

Intra-state sale, Bengaluru to Bengaluru: Web development services worth ₹80,000 to a Bengaluru-registered client. SAC 998314, GST rate 18%.

• Taxable value: ₹80,000
• CGST 9%: ₹7,200
• SGST 9%: ₹7,200
• Total invoice: ₹94,400
• Amount in words: Rupees Ninety-Four Thousand Four Hundred Only

Inter-state sale, Bengaluru to Mumbai: Same ₹80,000 service to a Mumbai-registered client.

• Taxable value: ₹80,000
• IGST 18%: ₹14,400 (single line, no SGST/CGST split)
• Total invoice: ₹94,400
• Place of supply: Maharashtra (state code 27)

Same total, different tax distribution. The buyer claims input tax credit either way, but their accountant needs the right tax type on the invoice. Get this wrong and you'll be issuing a credit note and reissuing within days.

B2C invoice above ₹50,000: Camera equipment ₹65,000 plus 18% GST sold to an unregistered consumer in Pune from your Bengaluru store.

• Taxable value: ₹65,000; IGST 18%: ₹11,700; total ₹76,700
• Buyer's name and address must appear on the invoice (B2C above ₹50,000 rule)
• State of recipient: Maharashtra (place of supply for goods is delivery location)