Add GST to a base price or strip GST out of a tax-inclusive amount across the 0/5/12/18/28% slabs — with the GST broken into its equal CGST and SGST halves the way an intra-state invoice shows it.
What GST is
The Goods and Services Tax (GST) is India's single indirect tax on the supply of goods and services, in force since July 2017. It replaced a tangle of older taxes — VAT, service tax, excise and others — with one tax charged at each stage of the supply chain, where businesses claim credit for the GST they paid on inputs. For an end customer, GST is simply a percentage added to the price; for a registered business, it is collected on sales and offset against tax paid on purchases.
CGST and SGST vs IGST
GST is collected jointly by the Centre and the states, and how it splits depends on whether the buyer and seller are in the same state:
- Intra-state (same state): the tax is divided equally into CGST (Central GST) and SGST (State GST). An 18% sale becomes 9% CGST + 9% SGST. This is the split the calculator above shows.
- Inter-state (across states): the whole tax is charged as a single IGST (Integrated GST) — 18% IGST, with no CGST/SGST line. The Centre later apportions the state's share.
The total tax you pay is identical either way; only the heads on the invoice differ. The same 50/50 logic also applies within a Union Territory as CGST + UTGST.
Inclusive vs exclusive pricing
This is the difference the Add/Remove toggle handles:
- Exclusive (Add GST): the listed price is the base, and GST is added on top. ₹10,000 at 18% becomes a ₹11,800 invoice. Most B2B quotes are written this way.
- Inclusive (Remove GST): the price already contains GST and you want to back out the base. The base is the total ÷ (1 + rate), not the total minus the rate. A ₹11,800 inclusive price at 18% has a ₹10,000 base and ₹1,800 of GST. Retail MRP is typically tax-inclusive.
The 0 / 5 / 12 / 18 / 28% slabs
GST uses five main rate slabs. As a general guide to how items tend to be grouped:
- 0% — many unbranded essentials and basic food staples.
- 5% — household necessities and several mass-use items.
- 12% — processed foods and a range of standard goods.
- 18% — the most common slab, covering the bulk of goods and most services.
- 28% — luxury and "sin" goods such as cars, aerated drinks and tobacco, sometimes with an additional compensation cess on top.
The exact rate of any specific product or service is decided by the GST Council and revised periodically, so these are general groupings rather than item-level guidance. Always confirm the current rate for your item on the official GST portal or a recent invoice. This page is a calculation aid, not tax advice.
Frequently Asked Questions
How do I add GST vs remove GST?
Use the toggle. Add GST (exclusive) treats your amount as the base price and adds the tax on top — ₹10,000 at 18% becomes ₹11,800. Remove GST (inclusive) treats your amount as already containing GST and works backwards to the base — a ₹11,800 inclusive price at 18% has a ₹10,000 base and ₹1,800 of GST. The formula to back out GST is base = amount ÷ (1 + rate), so it is not the same as simply taking 18% off the total.
What is the difference between CGST, SGST and IGST?
They are the same total tax, split differently depending on where the buyer and seller are. For a sale within the same state (intra-state), GST is divided equally into CGST (Central GST) and SGST (State GST) — so 18% GST shows up as 9% CGST + 9% SGST on the invoice. For a sale across states (inter-state), the whole tax is charged as a single IGST (Integrated GST) instead — 18% IGST, no CGST/SGST. The amount you pay is identical; only the heads change. This calculator shows the CGST/SGST split.
Which GST slab applies to common goods and services?
In general terms, the five slabs are 0%, 5%, 12%, 18% and 28%. Unbranded food staples and many essentials sit at 0% or 5%; processed foods and several goods at 12%; the bulk of standard goods and most services at 18%; and luxury or "sin" items such as cars, aerated drinks and tobacco at 28% (often with an extra cess). The exact rate of any specific item is notified by the GST Council and changes from time to time, so always confirm the current rate for your product on the official GST portal or an invoice — this is a general guide, not item-level tax advice.
Is GST inclusive of the compensation cess?
No. The compensation cess is a separate levy on top of GST, charged only on a small set of "sin" and luxury goods (such as tobacco, aerated drinks and large cars). It is over and above the 28% slab, so a 28% GST figure does not include cess. This calculator computes only the GST split (CGST/SGST) and does not add any cess.
How is the base price calculated from a GST-inclusive amount?
Divide by one plus the rate. Base = inclusive amount ÷ (1 + GST rate), and GST = inclusive amount − base. For 18% that means base = total ÷ 1.18. So from a ₹1,180 inclusive bill at 18%, the base is ₹1,180 ÷ 1.18 = ₹1,000 and the GST is ₹180 — split as ₹90 CGST + ₹90 SGST for an intra-state sale.
Do I charge GST if my turnover is below the threshold?
In general, GST registration is mandatory once turnover crosses the prescribed threshold (broadly ₹40 lakh for goods and ₹20 lakh for services, with lower limits for some special-category states). Below the threshold, registration is usually optional, and small taxpayers may opt for the composition scheme with a flat lower rate. The thresholds and conditions are set by law and have exceptions, so confirm your position with the official GST portal or a professional — this calculator only does the arithmetic of a given rate.
Estimates are for information and education only — not financial, tax or investment advice. Verify current rates and rules with official sources.