A tax invoice is more than a bill. Under GST it is the document your customer uses to claim input tax credit, and the one a tax officer will ask for first. If a required detail is missing, your buyer can lose their credit — and you can face a penalty. The list of what must appear is set out in Rule 46 of the CGST Rules, 2017.
Here is that list in plain words, with notes on the points small businesses most often get wrong.
The details every tax invoice must carry
About you, the supplier
- Your name, address and GSTIN. Use the legal or trade name exactly as registered.
- An invoice number — consecutive, unique for the financial year, and no longer than 16 characters. It may use letters, numbers, hyphens (-) and slashes (/). You can run more than one series, for example one per branch, as long as each number is used only once in the year.
- The date of issue.
- Your signature or digital signature, or that of someone you have authorised.
About your customer
- If the buyer is registered: their name, address and GSTIN (or UIN).
- If the buyer is unregistered and the taxable value is ₹50,000 or more: their name and address, the delivery address, and the name and code of their state.
- If the buyer is unregistered and the value is below ₹50,000: record their name and address if they ask you to — and for a sale to another state, always show their state as the place of supply.
About what you supplied
- HSN code for goods or SAC code for services. How many digits you must show depends on your turnover — check the current CBIC notification for your bracket.
- Description of the goods or services.
- Quantity and unit for goods (for example, 12 NOS or 25 KGS).
- Total value of the supply, and the taxable value after any discount.
About the tax
- Rate and amount of each tax — CGST and SGST (or UTGST) for a sale within your state, or IGST for a sale to another state — plus cess, if any.
- Place of supply, with the state name, for an inter-state supply.
- Delivery address, if it is different from the place of supply.
- Whether tax is payable on reverse charge. Say "Yes" or "No"; do not leave it out.
Tax invoice or bill of supply?
You issue a bill of supply instead of a tax invoice when you cannot charge GST on the sale — if you are registered under the composition scheme, or the goods or services are exempt. A composition dealer must also print "composition taxable person, not eligible to collect tax on supplies" on the bill.
How many copies?
| Supply | Copies | Marked |
|---|---|---|
| Goods | Three | Original for recipient · Duplicate for transporter · Triplicate for supplier |
| Services | Two | Original for recipient · Duplicate for supplier |
When invoices are made and shared electronically, these copies are simply printouts or PDFs with the right marking.
When to issue the invoice
- Goods: on or before removal of the goods for delivery (or when they are made available to the buyer).
- Services: generally within 30 days of supplying the service.
Mistakes we see most often
- Gaps or repeats in the invoice series — for example restarting numbering mid-year, or reusing a cancelled number.
- IGST charged on a sale within the state, or CGST + SGST on a sale to another state. The tax type follows the place of supply — see our guide to CGST, SGST and IGST.
- Buyer GSTIN typed wrongly. The buyer will not see the credit in their GSTR-2B. Check the 15 characters before you save.
- Missing HSN codes, or one HSN for every item.
- Reverse charge line left off when it does not apply. Writing "No" is enough.
A quick checklist before you send
- Your GSTIN and the buyer’s GSTIN are both correct.
- The invoice number follows the last one in the series.
- Each line has an HSN or SAC code, quantity and unit.
- Tax type matches the place of supply.
- Totals, discounts and round-off add up.
- IRN and QR are printed, if you must e-invoice.
Billing software should do most of this for you: keep the series in order, pick the tax type from the buyer’s state and refuse to save a malformed GSTIN. Whatever you use, the checklist above is the part to keep in your head.
