GST in India

# GST in India

GST is one tax with separate parts. Which parts apply depends on where the supplier and the customer are.

The parts

• CGST (central) and SGST (state) apply when the supply is within one state. Each is half of the total rate.
• IGST (integrated) applies when the supply crosses state lines.
• Rates are set by the GST Council and change. Check gst.gov.in before you set up a rate.

Place of supply

The place of supply decides whether CGST and SGST or IGST applies. Pop Books records the place of supply on each document, along with the supply type (for example a sale to a registered customer, to an unregistered one, an export, or a sale under reverse charge). It starts from the customer's state: the ship-to state first, then the bill-to state, and your own state if neither is set. You can change it on the document. If the tax code on the document charges IGST when the place of supply is within your state, or CGST and SGST when it is another state, the document is flagged with a plain description of the mismatch so you can correct the code. The CGST, SGST and IGST split is kept per line, so the returns can show it.

Invoice rules

A tax invoice needs, at least:

1. Your GSTIN and the customer's GSTIN, where the customer is registered
2. A unique invoice number and the date
3. The description, quantity and value of each item
4. The tax rate and the tax amount
5. The HSN code for goods or the SAC code for services, depending on your turnover

Each line can carry an HSN or SAC code. For e-invoices, Pop Books makes the request file and keeps the IRN you paste back (see the e-invoice article). It never connects to the portal. You upload the file yourself.

The GST summary

The summary covers a period you choose:

• Section 3.1(a): outward taxable supplies (value) and the tax on them
• Section 3.1(c): nil-rated, exempt or untaxed supplies (value)
• Section 4A: input tax credit on purchases
• Section 6.1: net tax payable, after credit is set off in the legal order

The summary is for GSTR-1 and GSTR-3B. Pop Books also makes the GSTR-1 and GSTR-3B files for a month, can compare your bills with GSTR-2B, and can list the supplier invoices from IMS for you to accept or reject. You upload the files yourself on the GST portal. Pop Books does not file GST returns for you.

Filing

Your filing frequency depends on your turnover and registration. Check the due dates on gst.gov.in. Ask your chartered accountant if you are unsure which return to file.

Verify with your tax adviser. Last reviewed 2026-11.