BillmanQuick answer: To add GST, multiply by (100 + rate) ÷ 100. To remove GST from an inclusive price, multiply by 100 ÷ (100 + rate). Within your state, split GST equally into CGST and SGST; to another state, charge it all as IGST.
Adding GST to a price
GST = Price × Rate ÷ 100. Total = Price + GST. For ₹1,000 at 18%: GST is ₹180 and the total is ₹1,180.
Removing GST from an inclusive price
Taxable value = Price × 100 ÷ (100 + Rate). For ₹1,180 including 18%: ₹1,180 × 100 ÷ 118 = ₹1,000, so GST is ₹180. A common mistake is to take 18% of ₹1,180 (₹212.40) — that is wrong.
CGST, SGST and IGST
| Sale | Tax charged | ₹1,000 at 18% |
|---|---|---|
| Within your state | CGST + SGST (half each) | ₹90 + ₹90 |
| To another state | IGST (full rate) | ₹180 |
Common GST rates
GST 2.0, from 22 September 2025, simplified the slabs:
- 0% — essentials such as fresh vegetables, milk and unbranded atta
- 5% — most everyday goods, including packaged food and edible oil
- 18% — most other goods and services
- 40% — luxury and sin goods
- 12% and 28% — still used for a few items
- Special: 3% gold and silver, 0.25% rough diamonds
💡 Rates change from time to time. Always confirm your item’s rate on cbic-gst.gov.in.
Watch: GST added automatically in BillmanMake a GST bill in seconds — 1:22
FAQ
How do I remove 18% GST from a price?
Divide the price by 1.18. ₹1,180 ÷ 1.18 = ₹1,000 taxable value, and the GST is ₹180.
Is CGST + SGST the same as IGST?
The total is the same. CGST and SGST (half each) apply within a state; IGST applies to sales to another state.
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