GST Calculator

What is GST?

Goods and Services Tax (GST) is India’s tax on the supply of goods and services, charged at each stage of the supply chain and ultimately paid by the consumer. Since the GST 2.0 reform of 22 September 2025, most items fall in the 5% or 18% slabs, with 40% for demerit goods and 0% for essentials. Within a state the tax is split equally into CGST and SGST; between states it is charged as IGST.

This GST calculator adds GST to a price or removes it from a GST-inclusive price, at any rate, and shows the CGST/SGST or IGST split.

How this calculator works

Adding GST is straightforward: multiply the base price by the rate. Extracting GST from a price that already includes it is where people slip up — you cannot simply take 18% of the total. The tax-inclusive amount has to be divided by 1.18 to recover the base.

Within a state, GST is split equally into CGST (central) and SGST (state). For interstate supplies the whole amount is charged as IGST, which the centre later apportions.

Formula

Adding GST:
  GST   = base × rate ÷ 100
  Total = base + GST

Removing GST:
  Base  = total ÷ (1 + rate ÷ 100)
  GST   = total − base

Within a state: CGST = SGST = GST ÷ 2

Worked example

1. A ₹10,000 base price at 18% GST: GST = ₹1,800, total = ₹11,800, split as ₹900 CGST + ₹900 SGST.
2. Going the other way from a ₹11,800 inclusive price: base = 11,800 ÷ 1.18 = ₹10,000, so the GST was ₹1,800 — not ₹2,124, which is what 18% of the total would wrongly give.

Adding GST to ₹10,000

Removing GST from ₹10,000 (inclusive)

To remove GST, divide the inclusive price by (1 + rate) — at 18%, divide by 1.18. Taking 18% of the inclusive price overstates the tax.

Assumptions & important notes

Frequently asked questions