A GST calculator is an online tool that works out Goods and Services Tax (or VAT, or sales tax, depending on your country's term for it) on an amount instantly, without manual formulas. Enter a price, pick a tax rate, and it shows you the tax amount and the final total — useful for shopkeepers, freelancers, accountants, and anyone billing customers anywhere in the world.
Yes. Every rate button and tax label (CGST, SGST, IGST, or whatever your country calls it) is fully customizable and saved in your browser. Tap "Edit rates" to set your own percentages — for example 5% federal GST plus provincial HST for Canada, 10% for Australia's GST, or your local VAT rate — and tap directly on any label (like "CGST") to rename it to match your country's terminology. You can also turn off the India-specific CGST/SGST/IGST split entirely for a single combined tax line. The calculator remembers your setup on every future visit.
Type an amount on the keypad, tap a tax rate button, and choose Add Tax or Remove Tax. The result updates live, showing the tax breakdown and the total — no separate "calculate" button needed. India-based users get the current GST 2.0 slabs (0%, 5%, 18%, 40%) by default, and can switch to the pre-2025 rates or fully custom rates at any time.
Tax exclusive means the amount you enter doesn't include tax yet — the calculator adds tax on top to find the final price. Tax inclusive means the amount already has tax baked in — the calculator works backward to extract the tax portion and find the original taxable value. This calculator handles both: "Add" mode is exclusive, "Remove" mode is inclusive.
A reverse GST calculator (also called a tax extraction calculator) takes a final price that already includes tax and works out the original amount before tax, plus the tax component itself. For example, if a product costs 1,180 with 18% tax included, a reverse calculator shows the taxable value was 1,000 and the tax was 180. Use "Remove" mode on this calculator for that, with whatever rate applies where you are.
For sales within the same state (intra-state), GST splits equally into CGST (Central GST, collected by the central government) and SGST (State GST, collected by the state government) — each is half the total GST rate. For sales between different states (inter-state), the full GST is charged as IGST (Integrated GST), collected by the central government and apportioned to the destination state. This calculator switches between the two automatically using the Intra-state/Inter-state toggle.
For GST exclusive amounts: GST Amount = (Original Amount × GST Rate) ÷ 100, then add that to the original amount for the total. For GST inclusive amounts: Taxable Value = Total Amount ÷ (1 + GST Rate ÷ 100), and GST Amount = Total Amount − Taxable Value. For example, on 1,000 at 18% tax exclusive, the tax amount is 180 and the total is 1,180 — with whatever rate applies where you are.
Since the GST 2.0 reform took effect on 22 September 2025, India's GST structure has four main slabs: 0% for essentials (fresh food, healthcare, education), 5% for daily-use and mass-consumption goods, 18% as the standard rate covering most goods and services, and 40% for select luxury and sin goods like tobacco, pan masala, and premium vehicles. The earlier 12% and 28% slabs were merged into 5% and 18% respectively for most items.
The four GST 2.0 slabs cover different categories of goods and services based on whether they're essential, standard, or luxury items:
Use the rate buttons on this calculator to apply the correct slab once you know which category your item falls under.
Those rates were phased out for most goods and services under the new GST rate calculator structure effective September 2025. They're still useful for older invoices, historical comparisons, or specific composition-scheme cases, so this calculator keeps them available — tap "Need old rates (12% / 28%)?" below the rate buttons to switch to the legacy GST calculator with old slabs.
Yes — tap the matching rate button (5%, 18%, or 40%) and the breakdown updates instantly. This works as a dedicated 18% GST calculator, 5% GST calculator, or 40% GST calculator depending on which rate you select, with no need to type the percentage manually.
Yes, it's completely free with no sign-up required. All calculations happen instantly in your browser.
This calculator is built to feel like a real calculator app — full keyboard support, calculation history, and a keypad-driven interface rather than a plain input form. A dedicated browser extension version is in the works for quick access without opening a new tab.
Yes — tap the history icon at the top of the calculator to open a saved list of past calculations. Each entry shows the amount, rate, and breakdown, and can be copied, shared, or tapped to reload back into the calculator.
The standard GST calculation formula for invoices is: GST Amount = (Taxable Value × GST Rate) ÷ 100. If the transaction is within the same state, split that GST amount equally between CGST and SGST. If it's an inter-state transaction, the full amount is charged as IGST. This calculator applies the correct formula automatically based on the mode and rate you select.
Add this calculator to your home screen — opens like a real app, full screen, no browser bar, no app store needed.
Best on mobile — Android (Chrome) gets a one-tap install, iPhone/iPad (Safari) uses the Share menu above.