GST Invoice Format: Mandatory Fields and a Sample Layout

The GST invoice format is not a fixed template; it is a list of details that every tax invoice from a registered supplier must carry. In short: supplier and buyer details with GSTINs, a unique invoice number and date, HSN, description, quantity, taxable value, the GST rate and amount split into CGST and SGST or IGST, place of supply for inter-state sales, a reverse-charge indication and a signature. If any of these is missing or wrong, your buyer's input tax credit can be questioned.

For a wholesaler or distributor, the tax invoice is also the document your retailer files away, your accountant reconciles and your khata is based on. Getting the format right once, and then producing it the same way every time, saves a lot of back-and-forth later.

This is general guidance to help you set up and check invoices. GST rules change from time to time, so confirm anything specific to your business with your chartered accountant.

Mandatory fields in the GST invoice format

The details a tax invoice must contain are laid down in Rule 46 of the CGST Rules. Here they are in plain language:

Field	What to show
Supplier details	Name, address and GSTIN of the seller
Invoice number	A consecutive serial number, up to 16 characters, unique for the financial year
Invoice date	The date of issue
Recipient details	Name, address and GSTIN (or UIN) if the buyer is registered
Goods	Description and HSN code for each item
Quantity	Quantity and unit (pieces, boxes, kg, cartons)
Values	Total value and the taxable value after any discount
Tax	GST rate and tax amount, shown as CGST + SGST or as IGST
Place of supply	Required for inter-state supplies, with the state name
Reverse charge	Whether tax is payable on reverse charge
Signature	Signature or digital signature of the supplier or an authorised person

For unregistered buyers, the rules ask for extra details on larger bills, such as the buyer's name, address and delivery address with state, when the value crosses a set threshold. If you sell to walk-in customers too, ask your CA how those bills should look.

Why the buyer cares about each field

A retailer registered under the regular scheme claims input tax credit on what you charge. That claim depends on your invoice showing their correct GSTIN, the right tax heads and the right amounts, and on you reporting the same invoice in your own return. A wrong GSTIN or a missing invoice number is not just untidy; it can block the buyer's credit until it is corrected.

A sample GST invoice layout

Most B2B invoices follow the same top-to-bottom structure:

1. Header: "Tax Invoice", supplier name, address, GSTIN, phone.
2. Invoice block: invoice number, invoice date, order or challan reference.
3. Bill to: buyer name, address, GSTIN, state.
4. Place of supply: state name (and code) where the supply ends.
5. Item table: serial number, description, HSN, quantity, unit, rate, discount, taxable value, GST rate, tax amount, line total.
6. Tax summary: taxable value and tax per GST rate, split into CGST and SGST or IGST.
7. Totals: total taxable value, total tax, round off, invoice total and amount in words.
8. Footer: reverse charge (Yes/No), declaration, authorised signatory.

Here is an illustrative item table. The 5% and 18% rates are examples only, not the current rate for any particular product:

Item	HSN	Qty	Taxable value	GST rate	CGST	SGST	Total
Item A	1234	10 box	₹1,000.00	5% (example)	₹25.00	₹25.00	₹1,050.00
Item B	5678	4 carton	₹2,000.00	18% (example)	₹180.00	₹180.00	₹2,360.00
Total			₹3,000.00		₹205.00	₹205.00	₹3,410.00

For an inter-state sale, the CGST and SGST columns are replaced by a single IGST column at the full rate, and the place of supply must name the buyer's state.

If your rates are quoted inclusive of GST, the taxable value has to be worked back first. Our guide to the GST inclusive price shows the formula with examples.

Tax invoice, bill of supply and challan: which one?

Document	Who issues it	Shows GST?
Tax invoice	Regular GST-registered supplier selling taxable goods	Yes
Bill of supply	Composition dealer, or anyone supplying exempt goods	No
Delivery challan	Used to move goods without a sale, such as job work or approval basis	No tax charged

A composition dealer cannot issue a tax invoice or collect GST. Their bill of supply must say "composition taxable person, not eligible to collect tax on supplies". Our article on the composition scheme explains the trade-offs for kirana stores.

Common mistakes in GST invoices

• Wrong tax head. Charging CGST + SGST on an inter-state sale, or IGST within the state. The state codes in the two GSTINs are the first thing to check.
• Missing or short HSN. Showing fewer digits than your turnover requires, or none at all.
• Breaks in the number series. Skipped or repeated numbers, or restarting mid-year.
• Invoicing what was ordered, not what was delivered. If two cartons came back, the bill should not include them.
• Discount shown after tax. A discount given on the invoice should reduce the taxable value, not be subtracted from the final total.
• Old GSTIN or name. Buyer details copied from an old bill after the retailer has re-registered or changed address.

GST invoice checklist for wholesalers

Before an invoice leaves your shop or van, run through this:

• Seller and buyer GSTINs correct, with the right state codes?
• Next number in this financial year's series, with no gap?
• Every line has HSN, quantity, unit and the right GST rate?
• Taxable value correct, after discounts, and worked back properly from inclusive prices?
• CGST + SGST for intra-state, IGST for inter-state, with place of supply shown?
• Quantities match what was actually delivered?
• Totals, round off and amount in words agree?
• Signed, digitally or by hand?

Remember to keep copies. For goods, the rules generally expect an original for the buyer, a duplicate for the transporter and a triplicate for the supplier.

How MaalMitra helps

MaalMitra creates the tax invoice for wholesalers as part of the order flow, so the invoice follows the delivery instead of being typed afterwards.

• Invoice on delivery. A GST tax invoice is created when an order is delivered, and an instant counter sale is invoiced in the same step.
• Numbered per financial year. Invoices are numbered automatically per wholesaler and financial year. Check with your CA that the number format suits your business.
• Delivered quantities only. If an order was partly fulfilled or short-delivered, the invoice covers only what the retailer accepted, and the same amount goes to the khata.
• HSN and taxable value on every line. HSN is set per product, including through CSV bulk upload. Prices are treated as GST-inclusive, and each line shows the rate before GST, taxable value, GST rate and tax, with a rate-wise summary.
• CGST + SGST or IGST by GSTIN state. The invoice compares the state codes in the seller's and buyer's GSTINs. Without a buyer GSTIN, the supply is treated as within the seller's state.
• Round off, amount in words, print and PDF.

Check that your printed invoice carries every field your CA requires, such as the reverse-charge declaration and the authorised signatory.

MaalMitra does not file returns or generate e-invoices or e-way bills, so keep your CA or accounting software in the loop for those.

The bottom line

The GST invoice format is a checklist, not a design. Put every required field on the page, keep one clean number series per financial year, let the GSTIN state codes decide CGST + SGST or IGST, and bill only what you delivered. When in doubt about a field or a special case, ask your CA.

Want invoices drafted automatically from every delivery? Get started free with MaalMitra.