Multiply the price before tax by the rate and divide by 100: at 18%, GST on Rs 1,00,000 is Rs 18,000 and the invoice total is Rs 1,18,000. To pull GST out of a total that already includes it, the formula is GST = total minus total x 100 / (100 + rate), so Rs 1,18,000 at 18% holds Rs 18,000 of GST on a Rs 1,00,000 price. Since 22 September 2025 most goods and services sit in two slabs, 5% and 18%, with 40% on a few, so look up your HSN or SAC code first. Inside your state the tax splits evenly into CGST and SGST (5% on Rs 1,000 is Rs 25 plus Rs 25, total Rs 1,050); a sale to another state carries it all as IGST. ClearTax's free calculator does both directions and the split.
Part of GST on eChai Explore.
5 resources, 5 link-checked.
The Finance Ministry's 3 September 2025 release on GST 2.0: two main rates, 18% standard and 5% merit, a 40% rate for a few goods and services, effective 22 September 2025.
From pib.gov.in by Press Information Bureau
A current rate list under GST 2.0, with which goods and services moved to 5% and 18% from 22 September 2025.
From cleartax.in by ClearTax
A free calculator that works forward from a price or back from a GST-inclusive amount and splits the result into CGST and SGST or IGST, with the formulas written out.
From cleartax.in by ClearTax
A calculator for pulling the taxable value and the GST out of a price that already includes GST, with the central, state and integrated split.
From cleartax.in by ClearTax
The GST portal's lookup for the HSN (goods) or SAC (services) code that sets your rate.
From gst.gov.in by GSTN
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