GST Calculator (India)

Adding vs removing GST

The two directions use different arithmetic, and mixing them up is the most common GST error in small businesses. Adding 18% to ₹10,000 gives ₹11,800. But removing 18% from an inclusive ₹11,800 does not mean subtracting 18% of 11,800; it means dividing by 1.18 to recover the ₹10,000 base.

Getting this wrong on an inclusive price overstates the tax and understates your taxable value, which surfaces as mismatches in GSTR filings.

CGST + SGST or IGST?

The split depends on the place of supply. When supplier and recipient are in the same state or union territory, the tax splits equally into CGST (central) and SGST or UTGST (state), each at half the rate. When the supply crosses state lines, the whole amount is levied as IGST. The total tax is identical either way; only the accounting heads differ. The calculator shows both presentations with the toggle.

Common rates and where they apply

0.25% covers rough precious stones; 3% covers gold and jewellery; 5% applies to essentials like packaged food items, economy transport and small restaurants; 12% and 18% cover most goods and services, with 18% the default for services like software, consulting and telecom; 28% applies to luxury and sin goods such as large cars and aerated drinks, often with cess on top. Rates change through GST Council notifications, so verify the current rate for your HSN or SAC code before invoicing; the custom rate box handles any value including cess-inclusive rates.

Worked example: quoting a client correctly

You quote a client ₹50,000 for a service and the client assumes it includes GST. If you meant it as a base price, the invoice becomes ₹59,000 and an argument follows. Decide the convention before quoting: "plus GST" means add 18% (₹59,000 total); "inclusive of GST" means your actual revenue is 50,000 ÷ 1.18 = ₹42,373 and the government gets ₹7,627. The remove-GST mode above shows freelancers instantly how much of an inclusive quote they actually keep, which is worth checking before agreeing to a rate.

Reverse charge and composition, briefly

Two situations change who pays or how much. Under reverse charge (certain notified services, and some purchases from unregistered suppliers), the recipient pays the GST directly instead of the supplier collecting it; the arithmetic here still applies, only the payer changes. Composition scheme dealers pay a small flat rate on turnover and cannot charge GST on invoices at all, so if a composition supplier bills you "GST", the invoice is wrong on its face.