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GST Calculator

Add or remove GST at any slab rate — with CGST/SGST split shown automatically.

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How to use the GST Calculator

  1. Enter the Amount.
  2. Choose the GST Rate — 5%, 12%, 18%, 28%, 3% or 0.25%.
  3. Choose whether the amount is Exclusive (GST to be added on top) or Inclusive (GST already included).
  4. Press Calculate GST — base, GST and the CGST/SGST split appear instantly.

Adding vs removing GST

Exclusive (add GST): you have the pre-tax price. GST = amount × rate ÷ 100. A ₹5,000 product at 18% becomes ₹5,900.

Inclusive (remove GST): you have the MRP-style final bill and want the GST inside it. Base = amount ÷ (1 + rate/100). From a ₹5,900 inclusive bill at 18%, the base is ₹5,000 and GST is ₹900 — exactly what appears on a proper tax invoice.

GST slabs in India

SlabTypical goods & services
0.25%Rough & unpolished diamonds
3%Gold, silver, jewellery
5%Essentials, economy transport, some packaged food
12%Processed food, higher-end goods
18%Most services & standard goods
28%Luxury & sin goods, cars, aerated drinks

Rates change from time to time by GST Council notification — always confirm the current rate for your item before invoicing.

CGST, SGST and IGST — who gets what

On sales within a state, GST splits equally into CGST (centre) and SGST (state) — which is why the calculator shows both at half the slab rate.

On sales between states, the full amount is charged as IGST. The total tax is the same either way; only the split differs.

India's GST structure

GST launched on 1 July 2017 through the 101st Constitutional Amendment, replacing a web of central and state taxes (VAT, service tax, excise, octroi). The main slabs are 0% (essential goods like fresh produce), 5%, 12%, 18%, and 28% (luxury and sin goods, the latter with an extra compensation cess). Rates are set by the GST Council, a joint body of the central and state finance ministers.

Registration thresholds: businesses need GST registration when turnover crosses 40 lakh for goods in most states (20 lakh in the default category of states) and 20 lakh for services (10 lakh in special-category states). Small businesses can alternatively opt for the composition scheme and pay a small flat percentage.

CGST, SGST and IGST

GST on a sale inside your own state is split into CGST (central share) and SGST (state share). The same sale to another state attracts IGST, which the centre later distributes. That is why your restaurant bill in your home city shows CGST 2.5% + SGST 2.5%, while an inter-state invoice shows IGST 5% — same total, different split.

For consumers the useful skill is reverse extraction: since Indian MRPs are tax-inclusive, the GST inside a 1,999 rupee product at 18% is 1,999 x 18/118 = 304.73 rupees. Our calculator's reverse mode does exactly this, which is also how businesses claim input credit correctly.

Frequently asked questions

How do I remove 18% GST from a total?
Divide the total by 1.18. Example: ₹1,180 ÷ 1.18 = ₹1,000 base, GST = ₹180. The calculator's “Inclusive” mode does this for any slab.
What are the current GST slabs?
The main slabs are 0.25%, 3%, 5%, 12%, 18% and 28%, plus exempt items at 0%. The GST Council revises items periodically, so check the latest notification for your category.
Why does my bill show CGST and SGST separately?
Intra-state supplies must split GST into CGST (central share) and SGST (state share), each at half the rate. Inter-state supplies show IGST at the full rate instead.
Is this GST calculator free?
Yes — completely free, unlimited calculations, no sign-up required.

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