GST calculator
Add GST to a price, or pull the GST back out of a tax-inclusive amount. Splits automatically into CGST and SGST, or IGST for interstate supply.
The mistake that costs people money
Removing GST is not the same as subtracting the rate. If a customer pays you ₹1,180 inclusive of 18% GST, the tax portion is ₹180, not ₹212.40. Taking 18% off the inclusive figure understates your base and overstates your liability — and if you do it across a year of invoices, your books stop reconciling with your returns.
The correct arithmetic is to divide by 1 + the rate. This calculator does that when you switch it to “Including GST”.
GST rate slabs
| Rate | Typically applies to |
|---|---|
| 0% | Unbranded food staples, fresh produce, most books |
| 0.25% | Rough diamonds and precious stones |
| 3% | Gold, silver and jewellery |
| 5% | Essentials, transport, small restaurants, economy travel |
| 12% | Processed foods, business-class air travel, some apparel |
| 18% | Most goods and services — the default slab |
| 28% | Luxury goods, tobacco, aerated drinks (cess may apply) |
Rates are revised periodically by the GST Council. Confirm the current slab for your specific HSN or SAC code before invoicing.
GST calculation questions
How do I remove GST from an inclusive price?+
Divide by (100 + rate) and multiply by 100. On a ₹1,180 inclusive price at 18%, the base is 1180 × 100 ÷ 118 = ₹1,000 and the GST is ₹180. People often subtract 18% of the inclusive figure instead, which gives ₹967.60 — wrong, and it compounds across every invoice.
What is the difference between CGST, SGST and IGST?+
For a supply within one state the tax splits evenly between Central GST and State GST — 18% becomes 9% CGST plus 9% SGST. For a supply between two states the whole 18% is charged as a single Integrated GST. The total is identical either way; what changes is which government receives it and how you report it.
Which GST rate applies to what?+
There are five main slabs. 0% covers most unbranded food staples. 5% covers essentials, transport and small restaurants. 12% and 18% cover most goods and services, with 18% the most common. 28% covers luxury and sin goods, sometimes with an additional cess. Precious metals sit at special rates of 0.25% and 3%.
Do I charge GST if I'm not registered?+
No — and you must not. Collecting GST without a valid registration is an offence. If you're below the threshold and unregistered, you issue a plain invoice with no tax component. If you're crossing the threshold, register first.
Charging GST means filing GST
Every rupee you collect has to be reported in GSTR-1 and paid through GSTR-3B, every period, including the months you sell nothing. We handle that from ₹599/month.