A GST invoice is more than a bill — it is the document your buyer uses to claim input tax credit. If a required field is missing or wrong, your customer can lose that credit, which quickly turns into an awkward phone call and a reprinted invoice. Getting the format right the first time keeps everyone happy.
Here is what a compliant GST tax invoice needs to contain.
The mandatory fields
A tax invoice for the supply of goods or services should include:
- Your details: name, address and GSTIN of the supplier.
- Invoice number: a unique, consecutive serial number for the financial year (up to 16 characters).
- Invoice date.
- Buyer details: name, address and GSTIN of the recipient (for B2B).
- Place of supply and state code — this decides whether you charge CGST + SGST or IGST.
- HSN or SAC code for each item or service.
- Description, quantity, unit and rate for each line.
- Taxable value and any discount.
- Tax rate and amount split into CGST, SGST/UTGST or IGST.
- Total invoice value in figures.
- Whether tax is payable on reverse charge, if applicable.
- Signature or digital signature of the supplier.
For exports, add the endorsement ("SUPPLY MEANT FOR EXPORT…") and, where relevant, the shipping and conversion details.
Common mistakes that cause credit problems
- Wrong or missing GSTIN of the buyer — the single most common reason a customer's credit gets stuck.
- Wrong place of supply, leading to CGST/SGST charged where IGST was due (or vice versa).
- Missing HSN/SAC codes, or codes that don't match the item.
- Non-sequential invoice numbers or duplicate numbers across a financial year.
- Rounding differences between the line tax and the total.
Most of these are data-entry problems, and they are exactly the kind of thing software should prevent.
Let the software do the heavy lifting
When your invoicing is done by hand or in a spreadsheet, every one of these fields is a chance to slip. Good billing software fills them in for you: the GSTIN and place of supply come from the customer master, HSN codes sit on the item master, and CGST/SGST/IGST is worked out automatically from the states involved.
CraveInvoice applies the correct GST on every line, pulls HSN/SAC from your items, keeps invoice numbers sequential per financial year, and prints a clean, compliant tax invoice — with e-invoice IRN and QR where required.
A quick self-check
Before you finalise your invoice template, run through this:
- Are your GSTIN and the buyer's GSTIN both correct?
- Is the place of supply right, and is the tax split (CGST/SGST vs IGST) correct for it?
- Does every line have an HSN/SAC code, quantity, rate and tax?
- Is the invoice number unique and in sequence?
- Do the line taxes add up to the invoice total?
Nail those five and your invoices will hold up — and your customers will get their input credit without a fuss.