GST Invoice Mandatory Fields Checker | Campion CA Tools

Name, address, and GSTIN of the supplier

Full legal name as per GST registration, complete registered office address, and 15-digit GSTIN. All three are mandatory on every tax invoice.

Consecutive serial number (not more than 16 characters)

Invoice number must be in a running series for the financial year. Can contain letters, numbers, hyphens, and slashes. Must not exceed 16 characters. Example: INV-2024-001. Cannot be changed once issued (issue credit note instead).

Date of issue of invoice

Tax invoice must be issued at the time of supply. For goods: at delivery. For services: within 30 days of supply (45 days for insurance and banks). Date format must be unambiguous — DD/MM/YYYY recommended.

Name, address, and GSTIN/UIN of the recipient

For registered recipients: name, address, and GSTIN. For unregistered recipients (B2C supply): name and address only (GSTIN not available). For exports: name, address, and country. For supplies to embassies/missions: UIN instead of GSTIN.

HSN / SAC code for goods or services supplied

HSN (goods) or SAC (services) code is mandatory. Required digits: 4 digits if annual turnover <₹5Cr; 6 digits if ₹5Cr–₹50Cr; 8 digits if >₹50Cr. B2C invoices for <₹5Cr turnover: 4-digit HSN is mandatory.

Description of goods or services

Clear description of the goods/services supplied. Should match what is in your GSTR-1. For services, describe the nature of service. Vague descriptions like "miscellaneous" are not recommended and can be questioned during audit.

Quantity and unit of measurement (for goods)

For goods: quantity in appropriate unit of measurement (kg, litre, metre, no., box, etc.). UOM must be from the GSTN-specified list. For services: quantity may be "1 job" or hours/days as applicable.

Total value of supply (taxable value)

The value of goods/services before tax. This is the base on which GST is calculated. Must match the contract price minus any discounts shown on the invoice. Net of discount if discount is at invoice level.

Applicable GST rate (CGST/SGST/IGST rate %)

Rate of tax must be clearly mentioned: CGST% + SGST% for intra-state, or IGST% for inter-state. If multiple rates apply to different line items, show rate against each line. Common rates: 0%, 5%, 12%, 18%, 28%.

Amount of tax (CGST, SGST, or IGST separately)

Tax amount must be computed and shown separately for CGST and SGST (intra-state) or IGST (inter-state). Cess, if applicable, shown separately. Rounding to nearest rupee is acceptable under GST rules.

Place of supply (state name and state code)

Mandatory for inter-state supplies to determine IGST vs CGST+SGST. Also mandatory on all invoices to identify the state where tax revenue belongs. State code is the first 2 digits of GSTIN of the place of supply.

Whether supply is under reverse charge (RCM)

Statement "Reverse Charge Applicable: Yes/No" is mandatory on all invoices. If supply is under RCM (recipient pays tax), mention "Tax payable on reverse charge basis". If not under RCM, state "No" or leave as regular invoice.

Signature or digital signature of supplier / authorised signatory

Physical signature of the supplier or authorised signatory is mandatory. Digital signature (DSC) is accepted. Pre-printed signature or wet signature are both valid. For e-invoices, the IRN and QR code replace the physical signature requirement.