This free GST calculator helps you work out Goods and Services Tax on any amount in seconds. Choose whether your amount already includes GST or not, enter the amount and the applicable GST rate, and the calculator instantly shows the net amount, the GST amount and the total amount. It supports the standard Indian GST slabs of 5%, 12%, 18% and 28%, as well as any custom rate you enter. This tool is useful for businesses preparing invoices or quotes, and for individuals who want to verify the GST charged on a purchase. GST rates and rules are set and periodically revised by the GST Council, so always confirm the applicable rate for your specific goods or services against current official sources before relying on any figure for compliance or filing purposes.
Total Amount (Incl. GST)
GST Amount
Net Amount
Goods and Services Tax (GST) is a comprehensive, multi-stage, destination-based indirect tax levied on the supply of goods and services in India. It replaced a number of earlier indirect taxes such as VAT, Service Tax and Excise Duty with a single tax structure. GST is charged at each stage of the supply chain, with credit generally available for tax already paid at earlier stages, so that the tax is ultimately borne by the final consumer rather than compounding at every step.
GST Exclusive (adding GST to a base price):
GST Inclusive (extracting GST from a price that already includes it):
This calculator applies exactly these two formulas depending on the mode you select.
GST Exclusive: Product price ₹10,000 + 18% GST = ₹10,000 + ₹1,800 = ₹11,800 total
GST Inclusive: Total price ₹11,800 at 18% GST → GST amount ₹1,800, net amount ₹10,000
Set the calculator above to either scenario and it will reproduce these exact figures. Notice that both directions of the calculation on the same pair of numbers agree with each other — that's a useful way to sanity-check your own figures.
India's GST structure is built around a small number of standard slabs, though the exact rate applicable to a specific good or service, and the slabs themselves, are set and periodically revised by the GST Council. As a general guide:
Because GST rates and item classifications can and do change, always verify the current rate applicable to your specific goods or service against official GST Council notifications or the GST portal before using it for invoicing, filing or compliance purposes. This calculator will compute correctly for whatever rate you enter — it does not itself determine which rate applies to a given item.
For the same base price, a higher GST rate increases both the GST amount and the total payable. For example, ₹10,000 at 5% GST adds ₹500 (total ₹10,500), while the same ₹10,000 at 28% GST adds ₹2,800 (total ₹12,800) — try different rates in the calculator above on the same amount to see the effect directly. This is especially useful when comparing quotes or invoices that apply different GST rates to similar amounts.
GST in India is generally split into components depending on whether a transaction is within a state or between states. For a supply within the same state, GST is typically split into CGST (Central GST), collected by the Central Government, and SGST (State GST), collected by the State Government — together adding up to the total GST rate. For a supply between two different states, IGST (Integrated GST) is typically charged instead, collected by the Central Government. This calculator computes the total GST amount; it does not split the figure into CGST/SGST/IGST components, since that split depends on the nature of the transaction.
Input Tax Credit is a mechanism that generally allows a registered business to claim credit for GST already paid on its purchases, and set that off against the GST it owes on its own sales. This is designed to prevent tax from compounding at every stage of the supply chain. Eligibility for and the mechanics of claiming ITC depend on current GST rules and the nature of the goods, services and registration involved — this calculator does not calculate ITC, and businesses should refer to official GST guidance or a tax professional for ITC-specific questions.
Businesses commonly use a GST calculator to quickly work out the GST-inclusive price to quote a customer, verify the GST amount shown on a supplier's invoice, or reconcile figures while preparing an invoice or bill. Whether a business needs to register for GST, which return filing frequency applies, and which specific compliance obligations apply, depend on factors such as annual turnover and the nature of the business — these thresholds and rules are set by GST law and can change, so check current official guidance or consult a tax professional for registration and compliance questions specific to your business.
Every good and service under GST is classified using a code — HSN (Harmonized System of Nomenclature) codes for goods, and SAC (Services Accounting Code) for services. These codes are what actually determine the applicable GST rate for a specific item, and they're generally required on invoices above certain value or turnover thresholds. If you're unsure what GST rate applies to something you sell or buy, the starting point is usually to look up its correct HSN or SAC code on the official GST portal rather than guessing based on a similar-sounding product. This calculator doesn't look up codes or rates — you still need to identify the correct rate for your specific item before entering it here.
Under normal GST rules, the supplier collects GST from the buyer and pays it to the government. Under the Reverse Charge Mechanism, that responsibility flips: the recipient of the goods or service pays the GST directly to the government instead of the supplier. RCM typically applies to specific categories of supply defined by GST law — for example, certain services bought from unregistered suppliers, or specific notified categories of goods and services. If you're calculating GST on a transaction that falls under RCM, the same GST-exclusive and inclusive formulas used by this calculator still apply mathematically, but the compliance responsibility (who reports and pays it) is different from a normal forward-charge transaction. Check whether RCM applies to your specific transaction using current GST rules or a tax professional.
E-invoicing is a system under which certain businesses must generate invoices in a standardized electronic format and report them to a government portal, which then issues a unique Invoice Reference Number (IRN) and QR code for that invoice. Whether e-invoicing applies to a business depends on its aggregate turnover crossing a threshold set by GST rules, and that threshold has been revised downward over time to cover more businesses — so don't assume a business is exempt without checking the current applicable limit. This calculator can help you work out the GST figures to put on an invoice, but it does not generate e-invoices or IRNs itself.
The Composition Scheme is an alternative, simplified GST scheme available to certain small businesses below a turnover threshold, where the business pays GST at a fixed, generally lower percentage of turnover instead of the standard rate structure, files returns less frequently, but in exchange cannot charge GST separately to customers or claim Input Tax Credit on purchases. Whether a business is eligible, and the exact rates and turnover limits involved, are set by GST law and can change — this calculator uses the standard GST calculation method and is not designed for Composition Scheme rate calculations, which work differently (a flat percentage of turnover rather than tax added to a price).
Freelancers and small business owners in India who cross the applicable GST registration turnover threshold, or who fall into specific categories that require registration regardless of turnover (such as certain inter-state suppliers or e-commerce sellers), generally need to register for GST, charge it on their invoices, and file periodic returns. Many freelancers below the threshold are not required to register or charge GST at all. This calculator is useful either way — for a registered freelancer, it helps quickly work out the GST-inclusive amount to quote a client; for anyone trying to understand a client's or vendor's invoice, it helps verify whether the GST shown adds up correctly against the stated rate.
Exports of goods and services from India are generally treated as "zero-rated" under GST, meaning GST is not charged on the export itself, though the exporter may still be able to claim a refund of GST paid on inputs used to make that export, subject to current rules and procedures. Imports into India, on the other hand, generally attract IGST at the point of import, in addition to customs duty, calculated on the assessable value of the imported goods. If you're calculating GST on an import or export transaction, confirm the correct treatment (and any applicable exemptions or refund routes) under current GST and customs rules, since export/import GST treatment involves more moving parts than a standard domestic sale.
Before GST was introduced, India's indirect tax system involved multiple separate taxes layered on top of each other — including Excise Duty on manufacturing, Service Tax on services, VAT charged by states, and various other central and state levies, each with its own rules, rates and filing requirements. Because credit for tax paid at one stage often couldn't be claimed against tax owed at another (a "cascading" effect, informally called tax on tax), the effective tax burden could end up higher than any single quoted rate suggested. GST consolidated most of these into one tax with a more connected input-credit chain across the supply chain, which is part of why understanding a single GST rate on an invoice is generally simpler than reconstructing the old multi-tax structure — though real-world compliance still involves the additional layers (registration, returns, ITC rules, RCM, composition scheme, and so on) described above.
This calculator provides a mathematical estimate of GST, net amount and total amount based on the figures and rate you enter. It does not determine which GST rate or slab applies to a specific good or service, does not calculate Input Tax Credit, CGST/SGST/IGST splits, or any other compliance-specific figure, and does not account for exemptions, cess, or other charges that may apply. GST rates, thresholds and rules are set by the GST Council and tax authorities and can change; always verify current, applicable rates and rules from official sources or a qualified tax professional before using any figure for invoicing, filing or compliance purposes. ToolPlex does not provide tax or legal advice.
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GST rates are set and periodically revised by the GST Council. The standard slabs commonly referenced are 5%, 12%, 18% and 28%, with some goods and services nil-rated or attracting other rates. Always confirm the current rate for your specific item from official sources.
For GST registration, filing or specific compliance questions, consult a qualified tax professional. This calculator provides mathematical estimates only.