Every registered business making a taxable supply in India must issue a GST-compliant invoice. Getting the format wrong doesn't just look unprofessional — it can block your customer's input tax credit claim and trigger scrutiny during a GST audit.
Mandatory fields on a GST invoice
- ✓Invoice number & date: A unique, sequential invoice number for the financial year.
- ✓GSTIN of supplier and recipient: Both parties' 15-digit GST registration numbers.
- ✓HSN/SAC code: The classification code for the goods or service being billed.
- ✓Taxable value & tax rate: The value before tax, and the applicable GST rate (0%, 5%, 12%, 18%, or 28%).
- ✓Tax breakup: CGST + SGST for intra-state supply, or IGST for inter-state supply, shown separately.
A single missing field — most commonly the HSN code or an incorrect GSTIN — is the most common reason a customer's input tax credit claim gets rejected.
Intra-state vs inter-state invoices
When the supplier and recipient are in the same state, GST splits equally into CGST and SGST. When they're in different states, the full rate is charged as IGST instead. Getting this split wrong is one of the most common invoicing errors — a billing platform that auto-detects the state from the GSTIN removes this risk entirely.
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SleetHR runs GST billing, reconciliation, and sales pipeline in one platform.