GST in one paragraph
The Goods and Services Tax replaced a tangle of central and state levies in 2017 with one tax on almost everything bought and sold in India. Every price you see is either before GST (a quotation, a freelancer’s fee) or after it (an MRP, a restaurant bill) — and this calculator converts between the two in either direction, at any rate.
The new slabs (since 22 September 2025)
The GST 2.0 reform collapsed the old 5/12/18/28 structure into three working rates — 5% for essentials and everyday goods, 18% as the standard rate for most goods and services, and 40% as the demerit rate for sin and luxury items (tobacco, pan masala, aerated drinks, big cars). The old 12% and 28% slabs are gone — most 12% items moved down to 5%, most 28% items down to 18%. Two specials survived untouched: 3% on gold and jewellery (making charges at 5%) and 0.25% on rough diamonds, while exempt items (fresh food, most education and health, and — since the reform — individual life and health insurance premiums) stay at 0%. Old invoices at 12% or 28% remain valid history: use the Custom rate for those.
Adding vs removing — the mistake everyone makes
Adding is obvious: GST = price × rate, so ₹1,000 at 18% invoices at ₹1,180. Removing is where bills get miscomputed: the tax inside ₹1,180 is not 18% of 1,180 (₹212.40). The MRP already contains the tax, so you divide:
Base = inclusive price ÷ (1 + rate) → 1,180 ÷ 1.18 = ₹1,000, GST = ₹180
Same trap at a restaurant: a ₹1,050 bill at 5% is ₹1,000 of food and ₹50 of tax — shown on the bill as ₹25 CGST + ₹25 SGST. Those halves are one tax split between the Centre and your state; buy across state lines and it appears as a single IGST instead, for the identical amount.
Where a salaried person actually meets GST
Mostly as a consumer — but three cases are worth knowing. Freelancing on the side? GST registration triggers at ₹20 lakh of service turnover (₹40 lakh for goods), and export clients are zero-rated with paperwork. Renting? Residential rent to an individual is exempt; commercial rent runs at 18%. Buying gold? You pay 3% on the metal and 5% on making charges — factor it into the real cost of “investment” jewellery before comparing it with a SIP or FD. And since GST quietly raises the price of nearly everything, it is one of the forces behind the inflation line in your budget.