About this tool
Use this free GST calculator to compute tax on any base amount. Select your GST slab and instantly see CGST, SGST, total GST, and the final price including tax.
How to calculate GST in India
GST Amount = Base Price × (GST Rate ÷ 100). For intra-state sales, divide equally into CGST and SGST. For inter-state, apply the full rate as IGST.
When to use this calculator
Perfect for shopkeepers adding tax to bills, freelancers quoting GST-inclusive prices, and accountants verifying tax on invoices.
Frequently asked questions
How do I calculate 18% GST?
Multiply the base amount by 0.18 to get GST. For ₹10,000 base, GST is ₹1,800 and total is ₹11,800.
What is CGST and SGST?
For intra-state transactions, GST is split equally into CGST (Central) and SGST (State). Each is half the total GST rate.