Online GST Calculator India — Inclusive & Reverse Tax
Calculate GST amounts instantly with 5%, 12%, 18%, 28% slabs. Convert inclusive gross prices to net base cost or add tax with 1-click invoice generation.
Calculates GST extra over your base cost (Price + GST = Total).
GST Added (Exclusive)
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Try 30-Day Free TrialHow GST is Calculated: Inclusive vs Exclusive
Understand the mathematical formulas used by banks, ERP software, and tax professionals.
When price does NOT include GST:
Example: A contract work of ₹1,00,000 at 18% GST: Tax = (1,00,000 × 18) ÷ 100 = ₹18,000. Total billed = ₹1,18,000.
When price ALREADY includes GST:
Example: An MRP payment of ₹1,18,000 at 18% GST: Base = 1,18,000 ÷ 1.18 = ₹1,00,000. Extracted GST = ₹18,000.
Official GST Rates & Slabs in India
Standard rates applicable across goods, services, and contracting sectors
| Rate | Classification | Common Goods & Services Included |
|---|---|---|
| 0% | Exempt Goods & Services | Fresh grains, milk, fruits, unprocessed agricultural produce, postal services, basic education. |
| 5% | Essential Everyday Commodities | Domestic LPG, coal, tea, spices, apparel below ₹1,000, passenger transport services, rail freight. |
| 12% | Standard Processed & Work Items | Business computers, mobile phones, processed foods, non-AC hotel rooms, diagnostic kits. |
| 18% | Standard Commercial & B2B Services | Contractor works, IT & software, business consulting, banking, construction labor, restaurants. |
| 28% | Luxury Goods & High-Tax Commodities | Cement, automobiles, air conditioners, refrigerators, high-end electronics, luxury goods. |
Frequently Asked Questions
Everything you need to know about calculating and billing GST
What is the difference between GST Inclusive and GST Exclusive?
GST Exclusive means the price entered is the base price, and applicable GST will be added on top of it (e.g. ₹10,000 + 18% GST = ₹11,800). GST Inclusive (Reverse GST) means the price already includes the tax, such as an MRP or quotation final rate, and the calculator calculates the original pre-tax value (e.g. ₹11,800 inclusive at 18% = ₹10,000 base + ₹1,800 GST).
What is the formula to calculate reverse GST from an inclusive amount?
The formula is: Original Base Amount = Gross Amount / (1 + (GST Rate / 100)). For example, for ₹11,800 at 18% GST: Base = ₹11,800 / (1 + 0.18) = ₹10,000. The GST amount is ₹11,800 - ₹10,000 = ₹1,800.
How are CGST, SGST, and IGST calculated?
For transactions within the same state (Intra-state), the total GST rate is divided equally between Central GST (CGST) and State GST (SGST). For example, 18% GST becomes 9% CGST and 9% SGST. For transactions across state borders (Inter-state), the entire tax is levied as Integrated GST (IGST) at the full rate (18%).
Can I convert the calculated GST amount into a tax invoice directly?
Yes! Click the 'Create GST Invoice with this Amount' button on the calculator. It instantly pre-fills the net amount and tax rate into our free GST invoice generator so you can print or download a professional A4 invoice in seconds.
Which GST slab applies to my business or services?
In India, GST has four major slabs: 5% (essentials, basic transport), 12% (business computers, select processed goods), 18% (most commercial services, IT, consulting, contractor labor, manufactured goods), and 28% (luxury items, cement, air conditioners). If you have a composite supply or special contract rate, you can also enter a custom percentage.
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