GST Calculator
Calculate Goods & Services Tax for all India slabs — exclusive and inclusive modes — free & instant
Original amount
GST amount
Total amount
What is this GST Calculator?
This free GST calculator lets any business owner, accountant, freelancer, or consumer in India instantly calculate the correct Goods and Services Tax amount for any transaction. Whether you need to add GST to a price (GST Exclusive) or find out how much GST is hidden inside a price that already includes tax (GST Inclusive / Reverse GST), this tool handles both — for all standard Indian GST slabs (5%, 12%, 18%, 28%) and any custom rate.
The calculator also automatically shows the CGST and SGST split for intrastate transactions, and the equivalent IGST for interstate transactions — exactly as it would appear on a proper GST invoice.
How to use this GST Calculator — step by step
- Step 1 — Choose your mode: Click "GST Exclusive" if your price does NOT yet include GST (you want to add GST on top). Click "GST Inclusive" if your price ALREADY includes GST and you want to find the original amount and GST component separately.
- Step 2 — Enter the amount: Type the price in rupees. For Exclusive mode, this is the pre-tax price. For Inclusive mode, this is the final price the customer is paying (with GST already inside).
- Step 3 — Select the GST rate: Click one of the quick buttons — 5%, 12%, 18%, or 28% — or click "Custom" and type any rate in the field (e.g., 0.25% for diamonds, 3% for gold, 1.5% for specific items).
- Step 4 — Click "Calculate GST" or just change any field — results update instantly. You will see the Original amount, GST amount, and Total amount.
- Step 5 — Check the breakdown: Below the result cards, the calculator shows the full formula used, plus the CGST + SGST split for intrastate or IGST for interstate — ready to use on your invoice.
Real examples — Exclusive and Inclusive
Example 1 — GST Exclusive (adding GST): You are a freelance web designer charging a client ₹50,000 for a project. Your service attracts 18% GST. Select Exclusive mode, enter ₹50,000, click 18%. Result: GST = ₹9,000. Total invoice = ₹59,000. On the invoice: CGST 9% = ₹4,500 + SGST 9% = ₹4,500 (if same state) or IGST 18% = ₹9,000 (if different state).
Example 2 — GST Inclusive (removing GST): You bought a laptop for ₹82,600 (price tag includes 18% GST) and want to know the actual pre-tax cost for your accounts. Select Inclusive mode, enter ₹82,600, click 18%. Result: Original price = ₹70,000. GST = ₹12,600. This is the figure you claim as Input Tax Credit (ITC) if you are a GST-registered business.
Key features
- GST Exclusive mode: Add GST on top of a price — shows GST amount and final total
- GST Inclusive mode: Extract GST from a GST-included price — reverse GST calculation
- All standard slabs: Quick buttons for 5%, 12%, 18%, 28%, 0% and Custom rate
- CGST / SGST / IGST split: Intrastate and interstate tax breakdown shown automatically
- Full formula shown: Every calculation step is visible — useful for learning and verification
- 100% private: No data stored or sent — works entirely in your browser
GST in India — what every business owner and seller must know
GST (Goods and Services Tax) was introduced in India on 1 July 2017, replacing over 17 central and state indirect taxes — including VAT, excise duty, service tax, and octroi — with a single unified tax structure. Today, every business with annual turnover above ₹40 lakh (₹20 lakh for service providers; ₹10 lakh for special category states) must register for GST and charge it on their invoices.
Getting your GST calculation wrong — whether by applying the wrong slab, confusing exclusive with inclusive, or miscalculating CGST and SGST — can result in short-payment notices from the GST department, rejection of your GSTR filings, and denial of Input Tax Credit to your business customers.
The 3 most common GST calculation mistakes
Wrong slab applied
Products and services are classified under HSN and SAC codes that determine the exact GST rate. A restaurant meal in an AC restaurant attracts 18% — but the same meal from a non-AC restaurant or a food delivery platform attracts only 5% (with no Input Tax Credit). Applying the wrong rate means your customer either overpays or underpays, and your GSTR filings will not match.
Exclusive vs inclusive confusion
This is the single most common error. If a product is priced at ₹1,000 inclusive of 18% GST and you treat it as exclusive and charge another 18% on top — your customer pays ₹1,180 instead of ₹1,000. The correct pre-tax price is ₹847.46, not ₹1,000. Use Inclusive mode in this calculator to find the correct split before raising your invoice.
CGST/SGST vs IGST error
For a sale within the same state (e.g., seller in Maharashtra, buyer in Maharashtra), the 18% GST must be split as 9% CGST + 9% SGST on the invoice. For a sale across state lines (e.g., seller in Maharashtra, buyer in Karnataka), the full 18% must be charged as IGST — not CGST+SGST. Applying the wrong type leads to a tax mismatch that triggers a notice from GSTN.
Complete India GST slab guide with examples
0% GST — Nil rated: Essential food items like milk, curd, bread, fresh fruits and vegetables, eggs, unbranded flour and rice, books, newspapers, and bangles. No GST is charged on these. If you are a seller dealing only in nil-rated goods, you may still need GST registration above the turnover threshold but will have zero tax liability.
5% GST: Packed food items (paneer, frozen vegetables), tea, coffee (not in a café), edible oils, sugar, domestic LPG, economy class air travel, fertilisers, agri machinery, and affordable restaurants (non-AC). A packet of biscuits priced at ₹100 exclusive: GST = ₹5, Total = ₹105.
12% GST: Processed and packaged food, computers and laptops, mobile phones (handsets), business class air travel, non-AC hotels, most Ayurvedic medicines, and diagnostic kits. A ₹50,000 laptop: GST = ₹6,000, Total = ₹56,000.
18% GST: The most common rate. Covers most services — IT and software services, telecom, insurance, banking fees, CA/legal services, advertising, AC restaurants, hotel rooms (₹2,500–₹7,500 per night), most electronics, cosmetics, paints, and cement. A ₹1,00,000 software project: GST = ₹18,000, Total = ₹1,18,000.
28% GST: Luxury and demerit goods — passenger cars and SUVs (plus cess), motorcycles above 350cc, tobacco products, aerated drinks and soft drinks, luxury hotels (above ₹7,500 per night), casinos, and betting. A ₹10,000 bottle of aerated drink (wholesale): GST = ₹2,800, Total = ₹12,800.
Special rates — 3% and 0.25%: Gold, silver, and precious metals attract 3% GST. Rough diamonds and precious stones attract 0.25%. These require specific HSN codes on invoices.
Who needs to register for GST in India?
GST registration is mandatory if your annual aggregate turnover exceeds: ₹40 lakh for goods suppliers (₹20 lakh for most states for services); ₹20 lakh for service providers; ₹10 lakh for businesses in special category states (Manipur, Mizoram, Nagaland, Tripura). Additionally, all e-commerce sellers (on Amazon, Flipkart, Meesho, etc.) must register for GST regardless of turnover — even if they sell only ₹1.
Free, instant, no signup required.
Frequently asked questions
What is the difference between GST exclusive and GST inclusive?
GST Exclusive means the price you have entered does NOT yet include GST — you are adding tax on top of it. For example, if you charge ₹10,000 for a service and GST is 18%, the GST amount is ₹1,800 and the total invoice to the client is ₹11,800. This is the mode used when you are preparing an invoice and quoting a pre-tax price. GST Inclusive (also called Reverse GST) means the price you have entered ALREADY includes GST inside it. For example, if a product's MRP is ₹11,800 and you want to find the base price and the GST separately, Inclusive mode extracts ₹10,000 (base) and ₹1,800 (GST) from the total ₹11,800. Use this mode for claiming ITC or verifying supplier invoices.
How do I calculate 18% GST on ₹10,000?
Select GST Exclusive mode (your ₹10,000 is the pre-tax amount), enter 10000 in the amount field, and click the 18% button. The calculator shows: GST amount = ₹1,800 (18% of ₹10,000). Total = ₹11,800. For an intrastate transaction (both buyer and seller in the same state): CGST 9% = ₹900 and SGST 9% = ₹900. For an interstate transaction (different states): IGST 18% = ₹1,800. Your invoice should show either the CGST+SGST pair or IGST depending on where your buyer is located — never both on the same invoice.
How do I remove GST from a GST-inclusive price?
Select GST Inclusive mode, enter the total amount (with GST inside it), and select the applicable rate. The calculator uses the formula: Original amount = Total ÷ (1 + Rate/100). For example, to find the base price of an item sold at ₹59,000 including 18% GST: Original = ₹59,000 ÷ 1.18 = ₹50,000. GST = ₹59,000 − ₹50,000 = ₹9,000. This is the correct reverse GST calculation used for ITC claims, expense reimbursements, and verifying that a supplier has charged you correctly. A common mistake is to calculate 18% of ₹59,000 = ₹10,620 — this is wrong because it applies GST on a GST-inclusive amount.
What is the difference between CGST, SGST and IGST?
GST in India is a dual tax — shared between the Central Government and State Governments. For intrastate transactions (seller and buyer both in the same state), the total GST is split equally: half goes to the Centre as CGST, half to the state as SGST. So 18% GST = 9% CGST + 9% SGST. Both must be shown as separate line items on the invoice. For interstate transactions (seller and buyer in different states), the full GST is charged as IGST (Integrated GST), which the Centre collects and then transfers the state's share later. So 18% GST = 18% IGST on the invoice — no CGST or SGST. If you charge CGST+SGST on an interstate sale, it is an incorrect invoice and the recipient cannot claim ITC on it.
What are the main GST slabs in India?
India has five main GST rate slabs: 0% for essential items like milk, bread, fresh vegetables, eggs, and books. 5% for household necessities like packaged food, tea, coffee, domestic LPG, and economy air travel. 12% for processed foods, computers, mobile phones, and business class air travel. 18% — the most common rate — for most services (IT, telecom, insurance), AC restaurants, most electronics, and hotel rooms. 28% for luxury and demerit goods like cars, tobacco, aerated drinks, and luxury hotels. Special rates of 3% (gold, silver) and 0.25% (rough diamonds) also exist. The exact rate for your product or service is determined by its HSN code (for goods) or SAC code (for services) as notified by the GST Council.
Can I use a custom GST rate in this calculator?
Yes — click the "Custom" button and type any rate in the GST rate field. This is useful for goods and services that attract rates outside the standard slabs — for example, 0.25% for rough diamonds, 3% for gold jewellery, 1.5% for job work on certain textiles, or 6% for certain renewable energy equipment. The calculator accepts any rate between 0% and 100% and performs both Exclusive and Inclusive calculations correctly at that rate. Always verify the exact applicable rate for your HSN/SAC code at the official GST portal (gst.gov.in) before raising an invoice.
What is Input Tax Credit (ITC) and how does this calculator help?
Input Tax Credit (ITC) is the mechanism that prevents double taxation under GST. If you are a GST-registered business and you purchase goods or services for your business (and pay GST on them), you can deduct that GST from the GST you owe on your own sales — paying only the difference to the government. For example, if you pay ₹18,000 GST on raw materials (input) and collect ₹27,000 GST from your customer (output), you pay only ₹9,000 to the government. This calculator helps you determine the exact GST component in any GST-inclusive purchase invoice using Inclusive mode — which is the figure you can claim as ITC, provided your supplier has filed their returns correctly and the invoice is GST-compliant.