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GST calculator: add GST or take it out of a price.
Type a price, pick the GST rate, and see the taxable value, the GST and the CGST + SGST or IGST split, to the paisa.
Two ways to calculate GST.
Adding GST to a price: GST = price × rate ÷ 100, and the total is price + GST.
Taking GST out of a price that already includes it (an MRP): taxable value = price × 100 ÷ (100 + rate), and GST is the difference.
Amounts are worked out in paise, so CGST and SGST always add up to the GST exactly. If the GST is an odd number of paise, the extra paisa goes to SGST.
| Example | Taxable | GST | Total |
|---|---|---|---|
| Add 18% to ₹1,000 | ₹1,000.00 | ₹180.00 | ₹1,180.00 |
| MRP ₹105 with 5% inside | ₹100.00 | ₹5.00 | ₹105.00 |
| MRP ₹118 with 18% inside | ₹100.00 | ₹18.00 | ₹118.00 |
| Add 5% to ₹250 × 4 | ₹1,000.00 | ₹50.00 | ₹1,050.00 |
CGST, SGST, IGST and the rate.
Same state
Sale to a buyer in your own state: half the GST is CGST and half is SGST. 18% becomes 9% + 9%.
Other state
Supply to another state: the whole GST is IGST. 18% stays 18% IGST.
Which rate?
Since 22 September 2025 most goods are at 5% or 18%; a 40% rate covers a short list of luxury and sin goods, and some items are exempt. A few, like gold, have special rates.
Check before you file: the rate depends on your item's HSN code. This calculator is for quick sums at the counter, not tax advice; ask your CA if you are unsure.
GST calculator questions
How do I remove GST from a price that already includes it?
Divide the price by (100 + GST rate) and multiply by 100. That is the taxable value; the rest is GST. For ₹118 at 18%: 118 × 100 ÷ 118 = ₹100 taxable and ₹18 GST.
How do I add GST to a price?
Multiply the price by the GST rate and divide by 100, then add it. For ₹1,000 at 18%: GST is ₹180 and the total is ₹1,180.
When do I charge CGST and SGST, and when IGST?
When the buyer is in your own state, the GST is split half CGST and half SGST. When you supply to another state, the whole GST is IGST.
Which GST rate applies to my item?
It depends on the item's HSN code. Since 22 September 2025 most goods are at 5% or 18%, a 40% rate applies to a short list of luxury and sin goods, and some items are exempt. Check your item's rate with your CA.
GST on every bill, without a calculator.
KamaiPlus puts the right GST split on each bill line and makes the GSTR-1 file at month end. See GST billing.
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