What is a GST tax invoice?
A tax invoice is the bill a GST-registered seller gives when selling goods or services. It shows what was sold, its value and the GST charged. Your customer, if registered, uses it to claim input tax credit, and you use the same details to file your GST returns.
If you are under the composition scheme, you cannot charge GST to customers. You give a “bill of supply” instead of a tax invoice.
Fields every GST invoice must have
Under the GST invoice rules, a tax invoice should show these details:
| Field | What to write |
|---|---|
| Seller details | Your business name, address and GSTIN |
| Invoice number | A unique, serial number for the financial year (up to 16 characters, letters, numbers, “-” or “/”) |
| Invoice date | The date the bill is issued |
| Buyer details | Name, address and GSTIN if the buyer is registered |
| Place of supply | State name and state code, especially for sales to another state |
| Item details | Description, HSN code (goods) or SAC (services), quantity and unit |
| Value | Taxable value of each item after any discount |
| Tax | GST rate and amount, split as CGST + SGST, or IGST |
| Total | Total invoice value in figures (and ideally in words) |
| Reverse charge | Whether tax is payable on reverse charge |
| Signature | Signature or digital signature of the seller or an authorised person |
Tip: GST rules change from time to time. Use this as a checklist and confirm special cases with your CA.
CGST + SGST or IGST: which one to charge?
It depends on where the goods or services go. When the seller and the place of supply are in the same state, the sale is intra-state: split the GST equally into CGST and SGST. For example, 18% GST becomes 9% CGST + 9% SGST.
When the place of supply is in another state, the sale is inter-state: charge the full rate as IGST. Charging the wrong type is one of the most common mistakes on small business bills, and correcting it later takes extra work.
B2B and B2C bills
- B2B (to a registered business): always show the buyer’s name, address and GSTIN, because they will claim input tax credit from your bill.
- B2C (to a consumer): the buyer’s GSTIN is not needed. For larger bills to unregistered buyers, the buyer’s name, address and state are also expected, so keep these details when you can.
- HSN codes: businesses with turnover up to ₹5 crore must show at least 4-digit HSN codes on B2B invoices; above ₹5 crore, 6-digit HSN codes are needed.
Common GST bill mistakes
- Skipping or repeating invoice numbers, or starting a new series in the middle of the year.
- Charging CGST + SGST on an inter-state sale (or IGST on a local sale).
- Missing or mistyped GSTIN of the buyer on B2B bills.
- Wrong GST rate on an item because the rate was typed by hand.
- Calculation errors when discounts are given after tax instead of before tax.
- Handwritten bills that are hard to read and easy to lose.
Make correct GST bills with VyapaarMatrix
VyapaarMatrix Inventory & Billing takes care of the format for you. Add your GSTIN once in settings, save each product with its HSN code and GST rate, and every bill shows the correct CGST, SGST or IGST with serial invoice numbers.
- Print on thermal receipt printers or A4, with 10+ A4 bill designs.
- Scan barcodes so the right item and rate are added every time.
- Record cash, UPI, card or split payments and see what is still due.
Questions people ask
Yes, if it has all the required fields. But handwritten bills often miss details or have calculation mistakes, and they are hard to keep safely, which is why most businesses now use billing software.
Invoice numbers must be unique within a financial year. Many businesses restart their series at the start of a new financial year, for example with a new prefix.
No. If you are not registered under GST, you cannot charge GST. Give a simple bill without tax.
A tax invoice shows GST charged. A bill of supply is used when no GST is charged, for example by composition dealers or for exempt goods.