Free GST calculator. Zero forms.

If ₹20,000 is the GST-exclusive (taxable) value: GST = 20,000 × 18 ÷ 100 = ₹3,600.00, so the invoice total is ₹23,600.00 — split as CGST ₹1,800 + SGST ₹1,800 within a state, or IGST ₹3,600 across states. If ₹20,000 already includes GST, the base value is 20,000 × 100 ÷ 118 = ₹16,949.15 and GST = ₹3,050.85. The calculator above does both in one type.

It depends on the slab the item falls in. On a ₹1,000 taxable value: 3% → ₹30.00, 5% → ₹50.00, 18% → ₹180.00, 40% → ₹400.00 (0%-rated items carry no GST). If the ₹1,000 total already includes GST, GST at 18% = 1,000 × 18 ÷ 118 = ₹152.54. Pick the slab in the calculator and the answer appears instantly.

The 18% slab is the standard rate covering most goods and services: electronics and appliances, most packaged processed foods, most professional and IT services, restaurants (food portion), telecom, textiles above the 5% band, and — after the GST 2.0 reform of September 2025 — most items that previously sat in the old 12% and 28% slabs. Essential items (fresh food, education, healthcare) are 0% or 5%, and demerit goods like cars and tobacco move up to 40% with cess.

On a simple calculator: to add GST, multiply the amount by the rate and divide by 100, then add it to the base (₹10,000 × 18 ÷ 100 = ₹1,800 → total ₹11,800). To extract GST from a total, multiply the inclusive amount by the rate and divide by (100 + rate) (₹11,800 × 18 ÷ 118 = ₹1,800). Or use the dedicated GST calculator above — it also shows the CGST/SGST or IGST split automatically.

GST calculation has two directions. GST exclusive (adding): GST amount = base value × rate ÷ 100, invoice total = base + GST. GST inclusive (removing): base value = inclusive amount × 100 ÷ (100 + rate), GST = inclusive amount − base value. Both directions work at any slab on this page — intra-state supplies automatically split the tax into CGST + SGST halves.

GST (exclusive) = Value × Rate ÷ 100 · Invoice total = Value + GST. For a GST-inclusive amount: Base Value = Inclusive Amount × 100 ÷ (100 + Rate) · GST = Inclusive Amount − Base Value. Example at 18%: on ₹10,000 the GST is ₹1,800; inside an ₹11,800 inclusive total the GST is also ₹1,800 (11,800 × 18 ÷ 118).

Identify the rate that applies to the product or service, decide whether your price excludes or includes GST, then apply the formula: adding GST — multiply by rate ÷ 100; removing GST — multiply by rate ÷ (100 + rate). Keep two decimals (paise) and remember intra-state sales split the tax as CGST + SGST at half the rate each, while inter-state sales use IGST at the full rate.

After the GST 2.0 restructuring (September 22, 2025), the main slabs are 0%, 5%, 18% and a 40% demerit rate, with a special 3% rate on gold, silver and jewellery. Fresh food, unbranded essentials, education and healthcare are 0%; packaged essentials and most household goods are 5%; most goods and services are 18%; cars, tobacco and aerated drinks are 40% plus cess. Always confirm product-specific classification on the CBIC schedule.

A GST-inclusive total already has the tax inside it, so divide by the rate-inclusive factor: GST = Total × Rate ÷ (100 + Rate) and Base = Total × 100 ÷ (100 + Rate). At 18%: GST = Total × 18/118 — e.g. a ₹59,000 GST-inclusive purchase contains ₹9,000 of GST (59,000 × 18 ÷ 118), Base ₹50,000. The "Remove GST" mode does this for any total.

On a GST invoice, each line item is taxed separately: line taxable value × rate ÷ 100, summed into the invoice total. For intra-state supply, the tax line splits as CGST + SGST at half the rate each; inter-state shows IGST at the full rate. The invoice must also show supplier/recipient GSTIN, a consecutive invoice number, HSN/SAC codes and place of supply — the free GST invoice generator on this site builds all of this for you.

GST is India’s unified indirect tax (since 1 July 2017), replacing VAT, service tax and excise. It works as a credit chain: every registered seller charges GST on sales and pays net tax = output GST charged − input tax credit (ITC) taken on purchases, filed in GSTR-1 and paid via GSTR-3B. The tax burden economically lands on the final consumer, who gets no credit — which is why all-inclusive prices embed a tax portion you can extract.

GST is counted on the taxable value of each supply — the price actually charged for the goods or services before GST, as determined under Section 15 of the CGST Act (including non-monetary consideration and subsidies linked to the supply, after deducting discounts and statutory refunds). At each sale, tax = taxable value × rate, split into CGST + SGST within a state or charged as IGST across states, and tracked invoice-by-invoice through the credit chain.

Always on revenue — specifically on the taxable value of each supply — never on profit. GST is a consumption tax collected on behalf of the government: a business charges it on sales (output tax), credits the GST paid on purchases (input tax credit), and remits only the difference. Profit margins are irrelevant to the calculation; gross sales turnover matters for registration thresholds and return periods instead.

From a full (GST-inclusive) price: Base value = Full price × 100 ÷ (100 + Rate), and GST = Full price − Base value. At 18%, that is Full × 18 ÷ 118; at 5%, Full × 5 ÷ 105; at 40%, Full × 40 ÷ 140. Example: a ₹1,180 full price contains ₹180 GST and ₹1,000 base value (1,180 × 18 ÷ 118 = 180).

On the selling price — the transaction value actually charged for the supply — not on MRP. MRP is the tax-inclusive ceiling printed for consumers; sellers may charge below MRP, and GST then applies to the discounted transaction value after eligible deductions under Section 15. Where a price happens to equal MRP, the embedded GST portion is extracted with Base = Value × 100 ÷ (100 + Rate). The GST regime bases assessment on the value of supply, so MRP only matters as the printed inclusive ceiling.

The best GST calculator is one that is exact, works both directions and shows the real invoice split. This one computes in integer paise (no float drift), handles every slab plus custom rates, flips between Add/Remove GST and intra/inter-state supply instantly, shows CGST/SGST/IGST breakdowns, shares results via URL, is free without signup — and comes with a reverse GST calculator, invoice generator and VAT/sales-tax calculators for 7 more countries.

Yes — 100% free, no signup, no limits, no personal data. Your amounts never leave your browser; every calculation runs locally in JavaScript. The site also works in dark mode and is fully usable on mobile.

For a supply within one state (intra-state), GST splits between the Centre and the state — CGST plus SGST at half the headline rate each. For an inter-state supply, the entire tax is IGST at the full rate. The calculator shows both as soon as you toggle the type of supply.

Rates depend on the HSN/SAC classification of the product or service. Core combos: 5% for packaged essentials, 18% for most goods and services, 40% for demerit goods, 3% for gold. For certainty, check the official CBIC GST rate schedule or use a professional tool like Zoho Books for invoicing.

If you are a GST-registered business, GST you pay on purchases (shown separately as CGST/SGST/IGST on supplier invoices) can be claimed as input tax credit against your output liability in GSTR-3B, provided the supplier reported the invoice. This calculator helps you verify those invoice amounts first.

GST exclusive (adding GST): GST amount = base value × rate ÷ 100, and the invoice total = base value + GST. GST inclusive (extracting GST): base value = inclusive amount × 100 ÷ (100 + rate), and GST = inclusive amount − base value. The calculator does both instantly at any rate.

After the GST 2.0 reform (September 2025), the main slabs are 0%, 5% and 18%, with a 40% demerit rate on luxury and sin goods. Special rates apply to certain items — e.g. 3% on gold jewellery. The old 12% and 28% slabs were largely merged during the reform.