What a GST invoice must contain
A compliant tax invoice isn't just a receipt. It must carry specific fields: your GSTIN, a unique invoice number, the date, the buyer's details, an HSN code for each item, the taxable value, the tax rate, and the tax split. Miss any of these and the invoice isn't valid for GST. Here's each part in plain terms.
Your GSTIN and a proper number series
Every invoice shows your GSTIN — your GST registration number. It also needs a unique serial number from a continuous series. You can't repeat numbers or skip around. Most stores number invoices automatically, which keeps the series clean and audit-proof without you tracking it by hand.
The HSN code for every item
Each product needs its HSN code — the code that classifies goods for GST. It sets the tax rate, and it's mandatory on the invoice. How many digits you show depends on your turnover. Get the HSN right and the tax rate follows. Get it wrong and the whole invoice is off.
The right tax rate
GST applies in slabs — commonly 0, 5, and 18 percent, with higher slabs for some goods. Each product sits in a slab set by its HSN. Apply the correct rate to the taxable value. If your catalogue mixes slabs, every line can carry a different rate — exactly the kind of thing you don't want to compute by hand.
CGST + SGST, or IGST — the split that trips people up
This is the part sellers get wrong most. For a sale within your state, GST splits into CGST and SGST, half each. For a sale to another state, it's a single IGST at the full rate. The buyer's state versus yours decides which. Your invoice must show the right split, not just the total.
Credit notes for returns
When you refund or return an order, you issue a credit note — a matching document that reverses the tax. It links back to the original invoice. Skip it and your books and your GST returns fall out of step. Treat the credit note as part of the return, not an afterthought.
Let the store do the math
Getting every field, rate, and split right on every order by hand is a month-end nightmare. The Storemate applies GST at checkout and generates a compliant invoice — with HSN, the correct slab, and the right CGST/SGST or IGST split — automatically, per order. This is a starting point, not tax advice; for anything unusual, ask a qualified professional.