How to Create a GST Invoice: Required Fields and Format for India
Create a correct GST invoice with all mandatory fields. What to include, what to avoid, and templates for Indian businesses.
Why GST Invoice Accuracy Matters
A GST invoice is a legal document. Errors cause: GST ITC (Input Tax Credit) rejection for your buyer, GST department notices and penalties, and disputes with customers. Getting invoices right protects both you and your customers.
Mandatory Fields on Every GST Invoice
Per CGST Rules 2017, every B2B invoice from a GST-registered supplier must include:
Supplier details: Full legal name (as in GST registration), complete registered address, and 15-digit GSTIN.
Invoice identification: Unique consecutive invoice number (maximum 16 characters, alphanumeric, unique per financial year) and invoice date.
Recipient details (B2B): Name, address, and GSTIN of recipient.
Per line item: Description, HSN code (goods) or SAC code (services), quantity and unit for goods, unit price, discount, and taxable value.
Tax details: Applicable GST rate, CGST and SGST amounts (intra-state) or IGST amount (inter-state), and total invoice value in figures and words.
Other required fields: Place of supply, whether reverse charge applies, and supplier signature.
Invoice Numbering Rules
Must be consecutive within the financial year. Reset to 1 on April 1. Maximum 16 characters. Can include letters, numbers, hyphens, and slashes. No spaces.
Good formats: INV-2526-0001, ABC/25-26/001, GST-001-2526.
HSN and SAC Codes Required
Goods: HSN (Harmonised System of Nomenclature) code
Services: SAC (Service Accounting Code) code
Annual turnover up to Rs 5 crore: 4-digit HSN/SAC required
Annual turnover above Rs 5 crore: 6-digit HSN/SAC required
Exports: 8-digit HSN mandatory
Common SAC codes: 998313 (software development), 998314 (IT consulting), 9983 (other professional services)
Common Invoice Mistakes
Wrong GSTIN: Verify your customer's GSTIN on the GST portal before invoicing.
Missing place of supply: Determines whether CGST+SGST or IGST applies.
Incorrect tax calculation: Double-check CGST/SGST vs IGST based on whether sale is intra-state or inter-state.
Missing HSN/SAC: Non-compliance for turnover above Rs 5 crore attracts Rs 50,000 penalty per return.
Frequently asked questions
What are the mandatory fields in a GST invoice?
Supplier GSTIN and address, invoice number and date, recipient GSTIN (for B2B), line item descriptions with HSN/SAC codes, taxable value, applicable GST rate, CGST/SGST or IGST amounts, total value, and place of supply.
What is the maximum invoice number length under GST?
16 characters maximum. The invoice number must be alphanumeric (letters, numbers, hyphens, slashes), unique within the financial year, and consecutive.
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