GST Billing Guide for Retailers

What a valid GST invoice needs, and where retailers commonly go wrong.

What a GST invoice must include

A valid GST tax invoice generally needs:

Your business name, address, and GSTIN
A sequential, unique invoice number and date
Customer name and address (and GSTIN, if they're GST-registered)
Description of each item sold, with its HSN code
Quantity and unit price
Taxable value before tax
The applicable GST rate and amount, correctly split as CGST+SGST or IGST depending on whether the sale is within your state or across states (see our CGST vs SGST vs IGST guide)
The total invoice value

Current GST rate slabs

Following the GST 2.0 reform effective September 2025, most goods and services now fall into one of these slabs:

0% — essential items (certain food staples, life-saving drugs, educational materials)
5% — essential goods and select services
18% — the standard rate covering most manufactured goods and services
40% — luxury and "sin" goods (e.g. premium vehicles, tobacco, aerated drinks)

The older 12% and 28% slabs were largely phased out in this reform, with most items redistributed into 5% or 18%. Always confirm the current rate for your specific product — rate structures do get revised.

Common billing mistakes

Wrong tax split — charging CGST+SGST on an inter-state sale, or IGST on an intra-state one.
Missing or wrong HSN codes — see our HSN code guide.
Non-sequential invoice numbers — skipped or repeated invoice numbers can cause problems during filing or audit.
Manual calculation errors — working out tax by hand on every invoice is where small mistakes compound over hundreds of sales.

Why this is worth automating

None of the above is complicated in isolation, but doing it correctly on every single invoice, by hand, across hundreds of sales a month, is where errors creep in. HisaabBox computes the correct tax split and pulls in each product's HSN code automatically, so every invoice is built the same, correct way every time.

This page is general information, not tax advice. Confirm current GST rates and your specific filing obligations with a qualified GST practitioner.