GST Calculator India — FY 2026-27 (with HSN Code Lookup)
Calculate Goods and Services Tax (GST) for any item or invoice — add GST to a base price, or extract GST from a tax-inclusive amount. Supports all four official slabs (5%, 12%, 18%, 28%), gives you the CGST + SGST (intra-state) or IGST (inter-state) breakdown, and includes a searchable database of 12,000+ HSN codes.
🔎 HSN / SAC Code Lookup
Type a product or service name to find its HSN/SAC code and applicable GST rate.
What is GST and how is it calculated?
The Goods and Services Tax (GST) is a comprehensive indirect tax introduced in India on 1 July 2017 to replace a fragmented tax system that included excise duty, service tax, VAT, octroi, entertainment tax and a dozen state-level levies. GST is levied on the supply of goods and services at every stage of the supply chain, with the final consumer bearing the tax. Businesses get input tax credit at each step so the cumulative cascade is eliminated.
Four standard tax slabs exist in 2026:
| Slab | Goods / Services |
|---|---|
| 0% | Fresh vegetables, fruits, milk, eggs, salt, education, public healthcare |
| 5% | Edible oil, sugar, tea, coffee, packed branded grains, footwear <₹500, transport, restaurant non-AC |
| 12% | Butter, cheese, processed food, mobile phones, fertilizer, footwear >₹500, business class flights |
| 18% | Soap, toothpaste, cement, AC, refrigerator, restaurant AC, telecom, banking, software, most services |
| 28% | Cars, motorbikes, luxury items, aerated drinks, tobacco, online gaming, 5-star hotels (with cess) |
The GST math
Adding GST (when your price excludes GST): GST amount = base × (rate / 100). Final price = base + GST.
Removing GST (when your price includes GST): base = inclusive ÷ (1 + rate/100). GST = inclusive − base.
CGST + SGST split: for intra-state sales the GST is split 50/50 — if the rate is 18%, then CGST = 9% and SGST = 9% of the base amount. Both go to different governments (Centre and State).
IGST: for inter-state sales the entire GST is charged as IGST (Integrated GST) and later distributed between the Centre and the destination State by the GST Council settlement.
Real-world examples
Example 1 — Selling a laptop
A Delhi-based shop sells a laptop to a customer in Mumbai for ₹50,000 (exclusive). Laptops are taxed at 18%. Since this is an inter-state sale: IGST = ₹50,000 × 18% = ₹9,000. Invoice total: ₹59,000.
Example 2 — Restaurant bill
An AC restaurant in Bengaluru charges ₹1,180 inclusive for a meal. Restaurant GST is 18% (non-input-credit version 5% applies only to non-AC). Base = ₹1,180 / 1.18 = ₹1,000. GST = ₹180 (CGST ₹90 + SGST ₹90).
Example 3 — Mobile phone
A mobile is sold within Maharashtra for ₹12,000 (exclusive). Mobile rate is 12%. CGST = ₹720, SGST = ₹720, total payable = ₹13,440.
What are HSN and SAC codes?
HSN (Harmonized System of Nomenclature) is a globally accepted product classification system maintained by the WCO. India uses 4, 6 or 8-digit HSN codes depending on the supplier's annual turnover. As of 1 April 2026 the rules are:
- Turnover < ₹5 crore: 4-digit HSN required on B2B invoices, optional on B2C
- Turnover ≥ ₹5 crore: 6-digit HSN mandatory on all invoices
- Exports: 8-digit HSN always required
SAC (Services Accounting Code) is the equivalent for services — always 6 digits, starting with 99 (e.g. 998313 for IT consulting).
Common GST mistakes Indian businesses make
- Wrong slab — e.g. classifying packaged biscuits at 12% instead of 18%. Always verify the HSN.
- Missing reverse charge — some services (legal, GTA, advocate) attract reverse charge where the buyer pays GST.
- Place of supply errors — charging CGST+SGST when it should be IGST loses input credit for the buyer.
- Late GSTR-1 / GSTR-3B — ₹50/day late fee plus 18% interest on unpaid tax.
- Forgetting GST on advance receipts — for services, GST is due when advance is received.