Quick answer
Use this free online GST calculator to add GST to a price or remove GST from a GST-inclusive amount. It shows the net amount, CGST and SGST (or IGST for inter-state supply) and the total instantly.
Free Online GST Calculator
How to Use This GST Calculator
- Enter the amount.
- Select the GST rate (0%, 0.25%, 3%, 5%, 12%, 18%, 28% or 40%).
- Choose Add GST if your amount excludes GST, or Remove GST if it already includes GST.
- Tick Inter-state for IGST; leave it unticked for CGST + SGST within the same state.
GST Calculation Formula
Add GST: GST amount = Amount × GST rate ÷ 100; Total = Amount + GST amount.
Remove GST: Net amount = Amount × 100 ÷ (100 + GST rate); GST amount = Amount − Net amount.
Example: ₹10,000 at 18% GST: GST = ₹1,800, total = ₹11,800. Within the same state this is ₹900 CGST + ₹900 SGST; for an inter-state sale it is ₹1,800 IGST.
CGST, SGST and IGST
For a sale within the same state, GST is split equally into Central GST (CGST) and State GST (SGST). For a sale to another state, the full GST is charged as Integrated GST (IGST). Since 22 September 2025, most goods and services fall under the 5% and 18% slabs, with 40% for a small list of luxury and sin goods; the 12% and 28% options are kept for checking older invoices. always confirm the correct rate for your product or service with your CA, as rates can change.
Stop Calculating GST by Hand
If you make quotations and invoices every day, a CRM linked to Tally calculates GST automatically. See Tally CRM integration and free invoice generator.
Want to see GST-ready quotations in Sukam Apps CRM working for your business? Call 99142 49191 or WhatsApp us for a free demo.
Related Guides
Frequently Asked Questions
How do I calculate GST on an amount?
Multiply the amount by the GST rate and divide by 100. For ₹1,000 at 18%, GST is ₹180 and the total is ₹1,180.
How do I remove GST from a total amount?
Divide the total by (100 + GST rate) and multiply by 100 to get the net amount. For ₹1,180 at 18%, the net amount is ₹1,000 and GST is ₹180.
What is the difference between CGST, SGST and IGST?
Within the same state, GST is split equally into CGST and SGST. For inter-state supply, the whole GST is charged as IGST.
Is this GST calculator free?
Yes, it is free to use and works on mobile and desktop.
Which GST rate applies to my product?
It depends on the HSN or SAC code of your goods or services. Confirm the current rate with your CA.
