A GST invoice is the document a registered supplier issues for every taxable supply of goods or services. Getting the format right matters: it is the basis for your customer's input tax credit and for your own GSTR-1 filing.
This guide covers the mandatory fields a tax invoice must carry, how the tax split works, and the fastest way to raise a compliant invoice.
Mandatory fields on a GST tax invoice
Under the GST rules, a tax invoice should generally include the following details:
- Supplier's name, address, and GSTIN
- A consecutive, unique invoice number and the invoice date
- Customer's name, address, and GSTIN (for B2B supplies)
- HSN code for goods or SAC code for services
- Description, quantity, and taxable value of each item
- GST rate and the amount of CGST, SGST/UTGST, or IGST
- Place of supply (especially for inter-state supplies)
- Whether GST is payable on reverse charge
- Signature or digital signature of the supplier
CGST/SGST vs IGST — which to charge
The tax split depends on the place of supply. If the supplier and the customer are in the same state, the supply is intra-state and you charge CGST + SGST (each half of the total rate). If they are in different states, it is inter-state and you charge a single IGST at the full rate.
For example, an 18% supply within Maharashtra is billed as 9% CGST + 9% SGST. The same supply from Maharashtra to Gujarat is billed as 18% IGST.
Tax invoice vs bill of supply
A tax invoice is issued when you charge GST. A bill of supply is issued when you cannot charge GST — for example by a composition dealer or for exempt supplies — and it does not show a tax amount.
How to raise a GST invoice quickly
Save your business profile (name, GSTIN, logo, bank details) and your common items once. Then for each sale you pick the customer and items, the app applies the correct HSN and GST, and you share a PDF on WhatsApp or print it.
With PocketGST this works fully offline, so billing never stops when the network does.
Key takeaways
- A tax invoice must carry GSTIN, a unique number, HSN/SAC, taxable value, and the tax split.
- Same state → CGST + SGST. Different states → IGST.
- Use a bill of supply when GST is not charged (composition or exempt).
- Saving items and customers once makes repeat billing a few taps.
This guide is general information, not tax advice. GST rules and rates can change with GST Council notifications — verify specifics on the official GST portal or with your CA.
Put this into practice with PocketGST
Create GST-compliant invoices offline, apply the right CGST/SGST or IGST split, and prepare GSTR-1/3B helper reports — no signup on the Free tier.
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