How GST is calculated
Adding GST to a price
GST = price × rate ÷ 100 and total = price + GST.
Example: ₹5,000 at 18% → GST ₹900 → total ₹5,900.
Removing GST from an inclusive price
price before GST = total ÷ (1 + rate ÷ 100) and GST = total − price before GST.
Example: ₹1,180 including 18% → 1,180 ÷ 1.18 = ₹1,000 before GST, so the GST is ₹180. A common mistake is to take 18% of ₹1,180 (₹212.40), which overstates the tax.
CGST, SGST and IGST
The GST rate is the same everywhere. What changes is who collects it:
- Same state (seller and place of supply): the rate is split in half, CGST for the Centre and SGST (or UTGST) for the state. 18% becomes 9% + 9%.
- Different states: the full rate is charged as IGST. 18% stays 18%.
You pay the same total either way. The split matters for businesses claiming input tax credit and for filing returns.
GST rates (2025 onwards)
From 22 September 2025 ("GST 2.0"), most goods and services moved to two main slabs, with a higher rate for luxury and sin goods. Some typical examples:
| Rate | Typically applies to |
|---|---|
| 0% | Fresh fruit and vegetables, milk, education, healthcare services, individual life and health insurance |
| 5% | Many everyday and packaged foods, most medicines, restaurant food (most restaurants), economy air travel |
| 18% | Most goods and services: electronics, software and SaaS, telecom, professional services |
| 40% | Luxury and "sin" goods, e.g. pan masala, aerated sugary drinks, large cars |
| 3% / 0.25% | Gold, silver and jewellery / rough diamonds |
Rates depend on the exact HSN/SAC code and change by notification, so check the latest CBIC rate schedule for anything important. Older invoices may still show the earlier 12% and 28% slabs. Use "other" in the calculator for those.
Questions
How do I remove GST from a price?
Divide by (1 + rate/100). For ₹1,180 at 18%: 1,180 ÷ 1.18 = ₹1,000 before tax, so the GST is ₹180. Choose "including GST" above to do it automatically.
What is the GST on restaurant food?
Most restaurants charge 5% GST, without input tax credit. Restaurants in hotels with room tariffs above ₹7,500 a night charge 18%. If the bill has a service charge, GST applies to that too. Split a restaurant bill →
Is GST charged on alcohol?
No. Alcohol for human consumption is outside GST, and states charge VAT on it instead. That's why a bar bill can show GST on food and VAT on drinks. Doodle Bill handles both on the same bill.
Can I claim back the GST on my expenses?
If you're GST-registered and the purchase is for business, you can usually claim input tax credit (ITC), provided the invoice shows your GSTIN. Some credits are blocked under Section 17(5), such as food and beverages, beauty and health services, and personal-use items. Check with your CA.