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GST calculator

Add GST to a price or remove it from an inclusive price, with the CGST and SGST split.

Updated

GST is
GST rate
Total including GST
₹1,180.00₹1,000.00 + 18% GST
Net amount
₹1,000.00
GST amount
₹180.00
Gross amount
₹1,180.00

Sale within a state

CGST at 9%
₹90.00
SGST at 9%
₹90.00

Sale between states

IGST at 18%
₹180.00

How to calculate GST

  1. Choose Add GST if your amount is before tax, or Remove GST if tax is already included.
  2. Enter the amount and pick the GST rate, or choose Custom for any other rate.
  3. Read the net amount, the GST and the gross amount.
  4. Use the CGST and SGST split for a sale within your state, or the IGST figure for a sale to another state.

GST formulas

  • Adding GST: GST = amount × rate ÷ 100, and total = amount + GST.
  • Removing GST: amount before GST = total × 100 ÷ (100 + rate), and GST = total − amount before GST.
  • Within a state: CGST = SGST = GST ÷ 2. Between states: IGST = GST.

Amounts are rounded to the paisa, and the parts are worked out so they always add up to the total, as on an invoice.

Worked examples

Adding 18% to ₹1,000: GST = 1,000 × 18 ÷ 100 = ₹180, so the total is ₹1,180. Within a state that's ₹90 CGST and ₹90 SGST; between states, ₹180 IGST.

Removing 18% from ₹1,180: 1,180 × 100 ÷ 118 = ₹1,000 before GST, so the GST inside it is ₹180. Taking 18% off ₹1,180 would give ₹967.60, which is wrong, because the 18% was charged on ₹1,000.

GST on ₹1,000 at each rate

RateGSTTotalCGST + SGST
0.25%₹2.50₹1,002.50₹1.25 + ₹1.25
3%₹30₹1,030₹15 + ₹15
5%₹50₹1,050₹25 + ₹25
12%₹120₹1,120₹60 + ₹60
18%₹180₹1,180₹90 + ₹90
28%₹280₹1,280₹140 + ₹140
40%₹400₹1,400₹200 + ₹200

Since 22 September 2025, 5% and 18% are the two main GST slabs, with 40% for a short list of luxury and sin goods; 3% (gold) and 0.25% (rough diamonds) are special rates. Rates are set by the GST Council and can change, so confirm the rate for your goods or service. Compensation cess, where it applies, isn't included.

Common uses

  • Writing an invoice. Enter your price before tax and pick the rate to get the GST, the invoice total and the CGST and SGST amounts to show for a sale within your state.
  • Finding the price before GST. Shops and menus often show prices including GST. Switch to Remove GST to find the taxable value and the tax inside a bill.
  • Checking a bill's tax. Confirm that the GST charged on a bill matches the rate printed on it, and whether it should be CGST and SGST or IGST.

Questions

How do I calculate GST on an amount?

Multiply the amount by the rate and divide by 100, then add it on. At 18%, ₹1,000 carries ₹180 of GST, so the total is ₹1,180.

How do I remove GST from an inclusive price?

Divide the price by 1 plus the rate as a fraction. ₹1,180 including 18% GST is ₹1,180 ÷ 1.18 = ₹1,000 before tax, so the GST in it is ₹180. Taking 18% off ₹1,180 would give the wrong answer, because the 18% was charged on ₹1,000, not ₹1,180.

What are CGST, SGST and IGST?

On a sale within one state, GST is split equally between the central government (CGST) and the state (SGST): 18% becomes 9% + 9%. On a sale from one state to another, the whole amount is charged as IGST. The total tax is the same either way.

What are the GST rates now?

Since 22 September 2025 most goods and services fall under two main slabs, 5% and 18%, with 40% for a short list of luxury and sin goods. Special rates such as 3% for gold and 0.25% for rough diamonds still apply. The 12% and 28% picks are there for older invoices and any items still charged at those rates; check the current rate for your product or service.

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