What is it?
The GST Calculator adds GST to a price or takes it out, and shows the split into CGST + SGST or IGST.
Who is it for?
Shopkeepers, small business owners, accountants, freelancers raising invoices, and customers checking GST on a bill.
How to use it
- Enter the Amount and choose the GST rate.
- Under The amount is, choose Before GST (add GST) or Including GST (take GST out).
- Under Sale is, choose Within the same state (CGST + SGST) or To another state (IGST).
The most common mistake
To find GST inside an inclusive price, don’t take 18% of it. ₹1,180 including 18% GST is ₹1,000 + ₹180 GST. The tool divides correctly: price ÷ (1 + rate).
CGST, SGST or IGST?
- Seller and buyer in the same state: half CGST + half SGST (18% = 9% + 9%).
- Different states, or imports: IGST at the full rate.
Which rate?
GST rates were simplified in 2025 into fewer slabs, with special rates for some goods (like 3% for gold and silver). Find your item’s rate by its HSN or SAC code on the CBIC GST rate finder or ask your accountant: the rate depends on the exact item.
For a full tax invoice with GSTIN, HSN and both tax splits, use the Invoice Generator.
Worked example
₹5,900 including 18% GST: price before GST ₹5,000, GST ₹900 (CGST ₹450 + SGST ₹450 within a state).
Errors and how to fix them
- A result shows a dash (—): a box is empty or has something that is not a number in it, such as a comma or a letter. Type plain digits; use a dot for decimals.
- The GST looks too high on an inclusive price: check that The amount is is set to Including GST (take GST out). With Before GST, the tool adds GST on top.
- IGST shows instead of CGST + SGST: set Sale is to Within the same state (CGST + SGST).
Open the tool: GST Calculator (India)
Still stuck?
Contact support. Tell us which tool or page you were using, what you tapped, what you saw, and your phone or computer and browser (for example: Android phone, Chrome). We reply by email.
Questions, or an error not listed here?
Tell us in the comments: what you were doing, the exact message you saw, and your device and browser. We read every comment and add new fixes to this article.