GST basics used by the app
How Kapda Stock calculates GST on every bill — inclusive prices, CGST+SGST vs IGST from GSTIN state codes, HSN rates, discounts and non-GST bills.
You do not need to be a tax expert to bill correctly — the app does the arithmetic. This page explains the rules it follows so you can trust (and explain) the numbers on an invoice.
Prices are GST-inclusive#
The price you set on a product is the price the customer pays. On a GST bill the app works backwards to split each line into:
- Taxable value = line amount ÷ (1 + GST rate)
- GST = line amount − taxable value
So a ₹1,050 kurta at 5% GST shows a taxable value of ₹1,000 and GST of ₹50, and the customer still pays ₹1,050.
CGST + SGST or IGST?#
The split depends on where the buyer is registered, read from the first two digits of each GSTIN (the state code — 01 is Jammu & Kashmir, 27 is Maharashtra, and so on):
| Your GSTIN | Customer's GSTIN | Tax charged |
|---|---|---|
| Registered in state A | Registered in state A | CGST + SGST — the GST split into two equal halves |
| Registered in state A | Registered in state B | IGST — the full GST as one amount |
| Registered | Customer has no GSTIN (walk-in / unregistered) | CGST + SGST |
| No GSTIN in Settings | Anything | CGST + SGST |
GST rates and HSN codes#
Each product carries an HSN code and a GST rate, which must be one of the standard slabs: 0, 5, 12, 18 or 28%. The HSN code must exist in your workspace's HSN table.
Every workspace comes with the textile HSN range 5001–6310 pre-loaded, with a default rate per chapter:
| HSN chapter | Covers | Default rate |
|---|---|---|
| 50 | Silk, silk yarn and woven silk fabrics | 5% |
| 51 | Wool, fine or coarse animal hair; yarn and fabrics | 5% |
| 52 | Cotton, cotton yarn and woven cotton fabrics | 5% |
| 53 | Other vegetable textile fibres; paper yarn | 5% |
| 54 | Man-made filaments | 12% |
| 55 | Man-made staple fibres | 12% |
| 56 | Wadding, felt, nonwovens; twine and ropes | 12% |
| 57 | Carpets and textile floor coverings | 12% |
| 58 | Special woven fabrics; lace, tapestries, embroidery | 5% |
| 59 | Impregnated, coated or laminated fabrics | 12% |
| 60 | Knitted or crocheted fabrics | 5% |
| 61 | Apparel, knitted or crocheted | 5% |
| 62 | Apparel, not knitted | 5% |
| 63 | Other made-up textile articles; worn clothing | 5% |
These defaults are a starting point. Actual rates for garments and fabrics can depend on the sale value and change with GST Council notifications — set the correct rate on each product. See HSN codes & GST rates.
Discounts reduce the taxable value#
- A line discount (percentage or flat amount) comes off that line before tax is split out. It can never exceed the line amount.
- A bill discount is spread across all lines in proportion to their value, so GST is charged on what the customer actually pays.
Non-GST bills#
A bill can be created without GST broken out. The prices stay the same — the customer pays the same total — but no CGST, SGST or IGST is shown and the lines are recorded at 0%. When no line on an invoice has a GST rate above 0%, the invoice is treated as non-GST automatically.
Proforma invoices#
Proformas are estimates, not tax invoices. They are excluded from sales reports, finance, GST figures and your plan's monthly invoice count.
Related#
Last updated 15/09/2026