How GST Works in India: Slabs, CGST, SGST and IGST Explained
India's GST has five slabs and splits differently for intra-state and inter-state sales. Here's how to calculate it correctly — with a free tool that shows every split.
GST in one page
Goods and Services Tax (GST) in India is a destination-based tax with five main slabs: 0%, 5%, 12%, 18%, and 28%. The slab depends on the type of goods or services. The free GST Calculator covers all of them.
Adding and removing GST
To add GST, multiply the base price by (1 + slab/100):
₹1,000 × 1.18 = ₹1,180 at the 18% slab.
To remove GST from a GST-inclusive amount, divide by (1 + slab/100):
₹1,180 ÷ 1.18 = ₹1,000 base, so the GST is ₹180.
CGST, SGST and IGST
This is the part that catches people out:
- Intra-state sale (within the same state) — GST splits equally into CGST (central) and SGST (state). On 18% GST, that's 9% CGST + 9% SGST.
- Inter-state sale (between states) — the full amount is charged as IGST.
The calculator shows the base, the total GST, and both the CGST/SGST and IGST splits at once, so you can read off whichever applies to your transaction.
Keep your books clean as you grow
Calculating one invoice is easy. Tracking GST across hundreds of transactions, suppliers, and slabs is where good software pays for itself. Explore Pyalm's free business tools to keep your numbers tidy.