GST Calculator
Add GST to a price, or work backwards to remove GST from a GST-inclusive total. Enter an amount and a slab, choose intra-state (CGST + SGST) or inter-state (IGST), and see the taxable value, GST, and total instantly.
How to calculate GST
Goods and Services Tax (GST) in India is charged on the taxable value of a supply. Prices are quoted either exclusive of GST (the taxable value) or inclusive of GST (the total), and you often need to move between them.
- Adding GST: total = taxable value x (1 + rate). At 18%, a value of 1,000 becomes a total of 1,180, with 180 of GST.
- Removing GST: taxable value = total / (1 + rate). At 18%, a total of 1,180 works back to 1,000, with 180 of GST.
CGST, SGST, and IGST
GST is a destination-based tax. For an intra-state supply, the total GST is split equally into CGST and SGST. For an inter-state supply, a single IGST is charged at the full rate. The toggle above switches between the two so you can see the exact split.
GST slabs
Since the September 2025 GST reform (GST 2.0), the main slabs are 0% (exempt), 5%, and 18%, plus a 40% rate on select luxury and sin goods (the old 28% slab was removed). 18% applies to most services. The correct slab depends on the goods or services supplied. When you are ready to bill, the GST invoice generator builds a tax invoice with HSN/SAC codes, GSTIN, and the CGST/SGST/IGST split filled in for you.
Disclaimer: This tool provides an estimate based on the rate you enter. It does not determine the correct slab, place of supply, or whether a reverse charge or exemption applies. Verify GST treatment with a qualified professional.
Frequently asked questions
How do I add GST to a price? +
Multiply the taxable value by the GST rate, then add it to the taxable value. For example, on 1,000 at 18% GST: the GST is 180 and the total is 1,180. Choose 'Add GST' above and the calculator does this for you.
How do I remove GST from a GST-inclusive price? +
Divide the total by 1 plus the rate. At 18% GST, divide the inclusive total by 1.18 to get the taxable value, then subtract to find the GST. For 1,180 at 18%, the taxable value is 1,000 and the GST is 180. Choose 'Remove GST' to reverse-calculate.
What is the difference between CGST, SGST, and IGST? +
For an intra-state supply (supplier and place of supply in the same state), the GST is split equally into CGST (central) and SGST (state). For an inter-state supply (different states), a single IGST is charged at the full rate instead. Use the supply-type toggle to see the split that applies.