A GST invoice carries several pieces of information that can be checked against the supplier's registration. Doing so takes a couple of minutes and catches both innocent errors and the occasional deliberate one.
What a GST invoice normally shows
A tax invoice under GST is expected to carry, among other things:
- Supplier name, address and GSTIN
- A unique invoice number and date
- Recipient name, address and GSTIN where the recipient is registered
- Description of goods or services, with HSN or SAC codes
- Quantity, value and taxable value
- Rate and amount of tax, split into CGST and SGST/UTGST, or IGST
- Place of supply for inter-state supplies
- Signature or digital signature of the supplier
Exact requirements vary by document type and circumstance, so use this as a working checklist rather than a legal specification, and consult official sources where precision matters.
The checks, in order
1. Supplier GSTIN
Copy the GSTIN from the invoice and run a lookup. Confirm that a record exists and that the legal name returned matches the supplier name printed on the invoice. A trade name on the invoice and a different legal name in the record is normal and fine — but you should be able to see the connection.
2. Status as at the invoice date
The status you see today is today's status. If the invoice is old, a Cancelled status now does not necessarily mean the supplier was unregistered then. What does matter is the registration date: if the invoice predates it, the supplier was not registered when they issued the invoice.
3. The tax split
This is the check that catches the most genuine errors.
- Supplier and place of supply in the same state — the invoice should show CGST + SGST (or UTGST), each at half the total rate.
- Supplier and place of supply in different states — the invoice should show IGST at the full rate.
The supplier's state comes from the first two digits of their GSTIN. If those digits say Karnataka, your delivery address is in Tamil Nadu, and the invoice shows CGST and SGST, ask.
4. Rate and arithmetic
Check that the tax amount equals the taxable value multiplied by the rate. Rounding differences of a rupee are unremarkable; anything larger is worth querying. If the invoice quotes a GST-inclusive price, work backwards: taxable value equals the inclusive amount divided by one plus the rate.
5. Taxpayer type
If the lookup shows the supplier as a composition taxpayer, they cannot charge GST on the invoice in the way a regular taxpayer does, and a composition supplier's bill should say so rather than presenting a tax split.
6. HSN or SAC codes
Confirm the code plausibly matches what you actually bought. A code for an unrelated category may simply be a data entry mistake, but it affects the rate applied, so it is worth resolving.
7. Your own GSTIN
If you are registered, check that your GSTIN is printed correctly. An incorrect recipient GSTIN can cause the invoice not to appear against your account, which affects your credit.
Common mismatches and what they usually mean
- Invoice name differs from the legal name — usually a trade name in use; verify the link.
- GSTIN not found — usually a typo on the invoice, occasionally a number that was never issued.
- CGST and SGST charged on an inter-state supply — a supplier billing error.
- Invoice dated before the registration date — the supplier was not registered at the time.
- Supplier shown as cancelled — the registration has ended; query before paying.
Where to go next
- Read how to verify a supplier GSTIN.
- Read how to calculate GST to check the arithmetic.
- Read CGST, SGST and IGST explained.
- Verify a number with GST verification.