A GST calculator works out the GST amount and the gross/net price for a given slab rate. Enter the amount and pick the rate to see the GST component, the CGST/SGST split (intrastate) or IGST (interstate), and the final price in one step. The reverse mode extracts the base price from a GST-inclusive amount — e.g. ₹1,180 at 18% gives a base of ₹1,000 and ₹180 GST.
GST Calculator
Choose Add GST to go from an exclusive amount to inclusive, or Remove GST to reverse a GST-inclusive figure back to its base. The tool splits the tax into CGST + SGST for intrastate supply and shows the full IGST for interstate supply.
How the GST Calculator Works
GST Calculation Formula
| Calculation | Formula | Example at 18% |
|---|---|---|
| Add GST (exclusive → inclusive) | GST = Amount × Rate/100; Total = Amount + GST | ₹1,000 × 0.18 = ₹180; Total ₹1,180 |
| Remove GST (reverse — inclusive → exclusive) | Base = Total ÷ (1 + Rate/100); GST = Total − Base | ₹1,180 ÷ 1.18 = ₹1,000; GST ₹180 |
| Intrastate split (CGST + SGST) | CGST = GST/2; SGST = GST/2 | CGST ₹90; SGST ₹90 |
| Interstate (IGST) | IGST = full GST amount | IGST ₹180 |
Intrastate = supplier and place of supply in the same state (CGST+SGST). Interstate or imports = IGST at the full rate.
For consumer goods the printed MRP already includes GST, so use Remove GST to see the tax embedded in it. In B2B invoices, prices are normally quoted exclusive of GST — use Add GST there.
GST Slab Rates & Where They Apply
The rate you pick depends on the product/service HSN/SAC code. Common slabs at a glance:
| Rate | Typical items | CGST + SGST | IGST |
|---|---|---|---|
| 0% | Fresh produce, unbranded staples, education, health | — | — |
| 3% | Gold, silver & jewellery | 1.5% + 1.5% | 3% |
| 5% | Essential food, footwear ≤₹1,000, transport | 2.5% + 2.5% | 5% |
| 12% | Processed food, apparel, business-class air | 6% + 6% | 12% |
| 18% | Most services, electronics, restaurants (non-AC standard) | 9% + 9% | 18% |
| 28% | Luxury goods, cars, aerated drinks, tobacco | 14% + 14% | 28% |
Rates per the GST 2.0 slab structure effective FY 2025-26. Cess applies on some 28% luxury/sin goods over and above the rate.
For any intrastate supply the tax is split equally: 18% GST = 9% CGST + 9% SGST. CGST goes to the Centre and SGST to the State. For interstate supply or imports the entire amount is charged as IGST.
Not sure which slab or HSN code applies to your product?
Talk to a GST Expert →GST Calculator — Frequently Asked Questions
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