GST Invoice Generator

You have made a taxable sale and need a tax invoice, for a customer with a GSTIN or without one. Rule 46 of the CGST Rules, 2017 lists what it must show; other provisions set its number, its tax heads and whether it must be an e-invoice instead. The figures below were worked in the generator above.

The particulars Rule 46 lists

The rule has nineteen clauses, (a) to (s):

Rule 46 does not require the amount in words; it asks only for the total and taxable values. No signature is needed on an electronic invoice issued under the Information Technology Act, 2000. Export and SEZ invoices carry a set endorsement, with or without IGST paid, and an export invoice adds the delivery address and destination country.

The invoice number

Rule 46(b) asks for a consecutive serial number of up to 16 characters, in one or more series, using only letters, digits, hyphen and slash. It must be unique for the financial year, 1 April to 31 March by the invoice date. ST/2026-27/000001 is one character too long; ST/26-27/000001 fits.

The e-invoice portal (IRP) also rejects a number starting with 0, / or -, and since 1 June 2025 it converts numbers to upper case, so inv/26-27/0042 and INV/26-27/0042 count as one. The generator drops disallowed characters as you type and says so, which turns INV 26-27 #42 into INV26-2742. It cannot see your other invoices, so keeping numbers unique is up to you.

Place of supply

If you and the place of supply are in the same State or Union territory, the supply is intra-State; otherwise it is inter-State (IGST Act sections 8 and 7). The buyer's GSTIN is not the test.

For goods that move, the place of supply is where the movement ends. For goods sold to an unregistered buyer, it is the address recorded on the invoice (a State name is enough), or else your location. Sources conflict on when that clause, section 10(1)(ca), took effect: the CBIC portal's footnote says it is yet to be notified; CBIC Circular 209/3/2024-GST, the later statement, says 1 October 2023.

For most services it is a registered recipient's location, otherwise their address on record, or else yours (section 12(2)), with exceptions such as immovable property. The generator fills the place of supply from the buyer's GSTIN and applies no exceptions, so change it by hand when one applies.

CGST and SGST, UTGST or IGST

Intra-State supplies carry CGST + SGST, or CGST + UTGST in Andaman and Nicobar, Lakshadweep, Dadra and Nagar Haveli and Daman and Diu, Ladakh, Chandigarh and Other Territory. Delhi, Puducherry and Jammu and Kashmir have legislatures, so they count as States. Inter-State supplies carry IGST, as do exports and SEZ supplies even within one State, unless made under bond or LUT. The e-invoice portal's formulas, with the combined rate entered:

• CGST = SGST (or UTGST) = taxable value × rate ÷ 2
• IGST = taxable value × rate

A worked invoice within Maharashtra, tax rounded per line. The rates are illustrative; a real item's rate follows its HSN or SAC code.

Line 1's half is 999.99 × 9% = 89.9991, which rounds to 90.00. Delivered to Karnataka instead, IGST is 180.00 + 4.88 + 216.00 = ₹400.88, the same total. The two can differ by a paisa, since each half is rounded separately: ₹112.50 at 18% gives IGST of ₹20.25, but halves of 10.125 that round to ₹10.13 each, ₹20.26 in all.

Rounding, round-off and the amount in words

Per-line rounding rounds each line's tax to the paisa, as the portal does item by item. Rounding on the total works out tax once per rate, then shares it back so the lines still add up. Ten lines of ₹10.05 at 5%, intra-State:

Rounding to the rupee is optional and half up: round-off = rounded total − total before rounding. The worked invoice's 2,698.48 becomes ₹2,698.00, a round-off of −0.48, written in words in the Indian system as "Two Thousand Six Hundred and Ninety-eight Rupees Only". Paise are named when any remain. The number to words converter handles other amounts.

How a GSTIN checks itself

A GSTIN has 15 characters: a State code (there is no 28), the holder's PAN in characters 3 to 12, a registration count, Z for a regular taxpayer, and a check character. The generator recomputes the check by the widely used Luhn mod 36 method. Characters take values 0–9, then A = 10 up to Z = 35. Every second character from the left is doubled, a doubled value of 36 or more is folded by adding its two base-36 digits, and check = (36 − sum mod 36) mod 36.

For 27AAPFU0939F1Z the terms are 2, 14, 10, 20, 25, 30, 30, 0, 9, 6, 9, 30, 1 and 35 (Z doubled is 70 = 1 × 36 + 34, folded to 35). They sum to 221; 221 mod 36 = 5; 36 − 5 = 31, which is V. Change the second 9 to 8 and the check fails.

The check character is not in the GST Acts or Rules, so a mismatch is reported as a probable typo, and UINs that do not follow it are flagged without blocking the PDF. Only the GST portal can say whether a GSTIN is registered.

Customers without a GSTIN

From a taxable value of ₹50,000, the invoice must show an unregistered buyer's name, address, delivery address, and State name and code (Rule 46(e)); exactly ₹50,000 counts. Below that, only if the buyer asks.

If your turnover last year was ₹5 crore or less, the HSN code is optional on these invoices. Under ₹200, a buyer who wants no invoice need not be given one, but a consolidated invoice is due at the close of each day, except for multiplex cinema admission.

Exempt suppliers and composition taxpayers issue a bill of supply instead, and Rule 46A allows one invoice-cum-bill of supply for taxable and exempt items to an unregistered buyer. The generator makes neither.

Reverse charge

Every tax invoice must say whether tax is payable on reverse charge; the generator prints your answer but does not decide it. With Yes, the recipient pays the tax to the government and the supplier is owed the taxable value: on the worked invoice, ₹400.88 of tax and ₹2,298.00 (2,297.60 rounded) to the supplier.

The portal allows reverse charge on B2B and SEZ e-invoices, and the supplier still generates the IRN. A recipient paying reverse charge to an unregistered supplier issues a self-invoice within 30 days of receiving the supply (Rule 47A, from 1 November 2024); this tool does not make one.

HSN digits, copies and time limits

The first two rows apply from 1 April 2021 (Notification 78/2020-CT). The e-invoice portal accepts codes of 4, 6 or 8 digits only, so a 5-digit SAC fails there.

Goods invoices are made in triplicate, marked for the recipient, transporter and supplier; services invoices in duplicate; e-invoices in neither (Rule 48). A services invoice is due within 30 days of the supply, or 45 for a bank, insurer, financial institution or NBFC (Rule 47).

When the invoice must be an e-invoice

E-invoicing covers supplies to registered persons and exports once aggregate turnover, counted across every GSTIN on your PAN and excluding GST and cess, exceeds ₹5 crore in any financial year from 2017-18. That threshold, down from ₹10 crore, has applied since 1 August 2023 (Notification 10/2023-CT). Government departments, local authorities, SEZ units, banks, insurers, NBFCs, goods transport agencies, passenger transport and multiplex cinema admission are excluded.

If you are covered, an invoice issued any other way is not treated as an invoice (Rule 48(5)). The generator warns when your answers put an invoice in scope, and prints the Rule 46(s) declaration for an exempt business above the threshold, but it cannot get an IRN.

What this tool assumes

• A tax invoice only. It makes no IRN or e-invoice QR code, no B2C dynamic QR code (needed above ₹500 crore turnover), and no bill of supply, credit or debit note, cess or e-way bill. It cannot confirm that an invoice meets every rule that applies to you.
• The rate list holds the goods rates in force since 22 September 2025, without the 28% schedule omitted from 1 February 2026. Service rates were not checked; type yours in, up to 40%. Changes after 24 September 2026 are not reflected.
• Codes 25 and 26 count as one Union territory, as the law now defines it, though official code lists show both.
• Amounts are kept in whole paise, so printed lines add up to printed totals.
• The PDF cannot shape Devanagari or other Indian scripts, and points you to Print instead.
• Your draft stays in this browser and can be switched off. Nothing is uploaded.