A GST calculator answers the question invoices actually ask: is this price before tax or after tax? The page handles both.

Exclusive versus inclusive

Exclusive means the tax is added on top. On a base of 1,000 at 18%, GST is 180 and the buyer pays 1,180. Inclusive means 1,000 already includes the tax, so the base is smaller than 1,000 and the GST is the remainder. Pick the wrong mode and the invoice will not match the purchase order. The labels on the page are there so you do not have to remember which one you meant.

This is not a return, a HSN lookup, or advice about which rate applies. If you already know the rate, the page does the split.

  1. Open gstcalculator.beastbrowser.com.
  2. Enter the amount, the rate, and whether the amount is exclusive or inclusive.
  3. Read base, GST, and total.

A plain percent, without the GST split, is the percentage calculator.