What is GST?
GST (Goods and Services Tax) is India’s single indirect tax on the supply of goods and services. Most items fall into one of four slabs — 5%, 12%, 18% or 28%. Businesses need to add GST to their prices, and buyers often want to work out the base price hidden inside a GST-inclusive amount. This calculator does both, and splits the tax into CGST and SGST for you.
How to use the GST calculator
- Choose Add GST (to a net price) or Remove GST (from a gross price).
- Enter the amount.
- Pick a GST rate — 5%, 12%, 18%, 28% or type your own.
- See the base amount, GST, CGST/SGST split and total instantly.
How is GST calculated?
To add GST: GST = amount × rate ÷ 100, and total = amount + GST. To remove GST from a gross amount: base = amount ÷ (1 + rate ÷ 100), and GST = amount − base. For intra-state sales the GST is split equally into CGST and SGST.
A quick example
Sell an item for ₹1,000 plus 18% GST and the tax is ₹180 (₹90 CGST + ₹90 SGST), making the total ₹1,180. Working the other way, if a bill shows ₹1,180including 18% GST, the base price is ₹1,180 ÷ 1.18 = ₹1,000 and the GST portion is ₹180. The “Remove GST” mode is handy for reading a base price out of a final invoice.
Frequently asked questions
What’s the difference between CGST, SGST and IGST? For sales within a state, GST is split into CGST (central) and SGST (state). For inter-state sales the same total is charged as a single IGST.
Which slab applies to me? Rates depend on the goods or service — common slabs are 5%, 12%, 18% and 28%. Check the HSN/SAC code for your item.
Can I use a custom rate? Yes — type any rate into the box if your item uses a rate outside the presets.
Is anything stored? No — the calculation happens entirely in your browser.