GST Calculator

The Goods and Services Tax (GST) applies to nearly every product and service sold in India, and knowing the exact GST amount on any transaction is essential for businesses, freelancers, and consumers alike.

Reviewed by: CalcMojo Editorial Team

This GST calculator instantly computes the GST amount, CGST and SGST split (for intra-state transactions), or IGST (for inter-state transactions) at any of the standard GST rates: 5%, 12%, 18%, or 28%.

Enter an amount and choose whether you want to add GST to a base price or extract GST from an inclusive price. The calculator shows the pre-GST amount, GST amount, and total payable, along with the CGST/SGST or IGST split depending on the transaction type. This dual functionality is critical for billing, invoicing, and financial reconciliation — businesses need to add GST when pricing products, while consumers often need to extract the GST from a total amount to understand the actual cost.

Whether you are a business owner creating GST invoices, a freelancer charging clients, an accountant reconciling GST returns, or a consumer checking the tax component on a purchase, this tool handles the arithmetic instantly and accurately.

How GST Calculation Works

GST in India is a destination-based, multi-stage tax levied on the supply of goods and services. The calculation is straightforward but must account for the type of transaction and the applicable rate.

Adding GST to a Base Price (Exclusive Calculation):

GST Amount = Base Price x GST Rate / 100 Total Price = Base Price + GST Amount

Example: A product costs ₹1,000 before GST at 18%. GST Amount = 1,000 x 18/100 = ₹180 Total Price = 1,000 + 180 = ₹1,180

Extracting GST from an Inclusive Price (Inclusive Calculation):

Base Price = Inclusive Price x 100 / (100 + GST Rate) GST Amount = Inclusive Price – Base Price

Example: A service costs ₹1,180 inclusive of 18% GST. Base Price = 1,180 x 100 / 118 = ₹1,000 GST Amount = 1,180 – 1,000 = ₹180

The inclusive calculation is particularly important for consumers and businesses that display MRP (Maximum Retail Price), which is always GST-inclusive. To know the actual pre-tax cost and tax component, the reverse calculation is necessary.

GST Rates in India: The Four-Tier Structure

India’s GST operates on a four-tier rate structure, plus special rates for specific categories.

5% GST. Applied to essential goods and services: packaged food items, economy-class air travel, transport services, small restaurants (without input tax credit), fertilizers, and basic life necessities. This is the lowest standard rate, designed to keep essential items affordable.

12% GST. Applied to processed foods, business-class air travel, some textile products, smartphones, and various manufactured goods. This is the moderate rate for items that are not essential but not luxury either.

18% GST. The most common rate, applied to most goods and services: financial services, telecommunications, IT services, restaurants with air conditioning (with ITC), hair care products, electronics, and most professional services. Most B2B transactions fall under this rate. Freelancers and consultants typically charge 18% GST on their invoices.

28% GST. Reserved for luxury and demerit goods: automobiles, cement, consumer durables like washing machines and air conditioners, aerated drinks, tobacco products, and luxury hotels (room tariff above ₹7,500). Some items in this category also attract a GST compensation cess on top of the 28% rate.

Special Categories:

• 0% (Exempt): Fresh fruits, vegetables, milk, eggs, unprocessed food, healthcare services, educational services, books, and newspapers
• 0.25%: Rough diamonds and precious stones
• 3%: Gold, silver, and platinum
• Composition Scheme: 1% to 6% for small businesses with turnover below ₹1.5 crore (₹75 lakh for services)

CGST, SGST, and IGST: Understanding the Split

The GST amount is split differently depending on whether the transaction is within a state or across state borders.

Intra-State Transactions (Within the Same State): The GST is split equally between CGST (Central GST) and SGST (State GST). For an 18% GST transaction within Maharashtra, the buyer pays 9% CGST to the central government and 9% SGST to the state government. The total rate remains 18%.

Inter-State Transactions (Between Different States): The full GST is charged as IGST (Integrated GST) to the central government, which then distributes the state’s share to the destination state. For an 18% GST transaction from Maharashtra to Karnataka, the buyer pays 18% IGST.

Practical Impact for Businesses: The CGST/SGST vs IGST distinction matters for input tax credit (ITC). CGST credit can only offset CGST liability, and SGST credit can only offset SGST. IGST credit, however, can offset any of the three. This cross-utilization makes IGST credit more flexible, which is relevant for businesses purchasing from suppliers in other states.

GST for Freelancers and Service Providers

If you are a freelancer, consultant, or service provider in India, GST applies to your services once your aggregate turnover exceeds ₹20 lakh per year (₹10 lakh for special category states).

Registration Threshold:

• ₹20 lakh for most states
• ₹10 lakh for special category states (northeastern states, Himachal Pradesh, Uttarakhand, etc.)
• ₹40 lakh for exclusive goods suppliers in most states

Rate for Services: Most professional services (IT, consulting, design, marketing, legal, accounting) attract 18% GST. Some services like restaurant services, transport, and accommodation have specific rates.

Invoicing: GST invoices must include your GSTIN, the client’s GSTIN (for B2B), HSN/SAC codes, the taxable amount, GST rate, and the CGST/SGST or IGST split. This calculator helps you determine the correct GST amount for each invoice.

Input Tax Credit: As a registered service provider, you can claim ITC on GST paid on business expenses: office rent, software subscriptions, professional tools, internet, and travel. This effectively reduces your net GST outflow. Maintaining proper documentation and filing GST returns on time is essential to claim ITC.

GST Return Filing and Compliance

Registered businesses must file GST returns based on their turnover and registration type.

GSTR-1: Outward supplies (sales) filed monthly by the 11th of the next month (or quarterly for businesses with turnover below ₹5 crore under QRMP scheme).

GSTR-3B: Summary return with tax payment, filed monthly by the 20th (or quarterly under QRMP).

GSTR-9: Annual return filed by December 31 of the next financial year.

Late Filing Penalty:

• GSTR-1 and GSTR-3B: ₹50 per day (₹25 CGST + ₹25 SGST) for regular returns, ₹20 per day for nil returns. Maximum penalty: ₹5,000 per return.
• Interest on late tax payment: 18% per annum on the outstanding tax amount.

Accurate GST calculation on every invoice and transaction is the foundation of compliant GST filing. Errors in GST computation cascade into mismatches between GSTR-1 and GSTR-3B, triggering notices from the GST department.

GST Composition Scheme

Small businesses with aggregate turnover below ₹1.5 crore (₹75 lakh for service providers) can opt for the Composition Scheme, which offers simplified compliance at lower rates.

Composition Rates:

• Manufacturers: 1% GST (0.5% CGST + 0.5% SGST)
• Restaurants: 5% GST (2.5% CGST + 2.5% SGST)
• Other suppliers: 1% GST
• Service providers: 6% GST (3% CGST + 3% SGST)

Restrictions:

• Cannot collect GST from customers (tax is paid out of the seller’s margin)
• Cannot claim input tax credit
• Cannot make inter-state supplies
• Cannot supply through e-commerce platforms
• Must file only one quarterly return (CMP-08) instead of monthly GSTR-1 and GSTR-3B

The Composition Scheme is ideal for small local businesses with minimal inter-state transactions and low-value inputs. However, the inability to claim ITC means the effective tax burden may be higher than regular registration for businesses with significant input costs.

Impact of GST on Common Purchases

Understanding GST on everyday purchases helps consumers make informed decisions.

Dining Out: Restaurants without AC charge 5% GST (no ITC). AC restaurants and those with liquor licenses charge 5% GST. Five-star hotels charge 18% GST on food and beverages. A ₹2,000 restaurant bill at 5% GST includes ₹95 in tax (extracted from inclusive price) or ₹100 added to the base price.

Online Shopping: Most products on e-commerce platforms include GST in the displayed price. Clothing below ₹1,000 attracts 5% GST; above ₹1,000, it is 12%. Electronics generally attract 18%. Luxury items like watches and perfumes attract 28%.

Professional Services: If you hire a CA, lawyer, architect, or consultant, expect 18% GST on their fees. A ₹50,000 consulting fee becomes ₹59,000 inclusive of GST.

Real Estate: Under-construction properties attract 5% GST (1% for affordable housing) without ITC. Ready-to-move properties with completion certificates are exempt from GST. Stamp duty applies separately.

Use this calculator alongside the Income Tax Calculator (Old vs New) to understand both direct and indirect tax impacts on your finances. For loan-related purchases, check the total cost including GST with the EMI Calculator.

This calculator provides estimates. Actual returns depend on your financial institution’s terms.

Frequently Asked Questions

How do I calculate GST on a product?

To add GST to a base price: multiply the price by the GST rate and divide by 100. For a ₹1,000 product at 18% GST, the GST amount is ₹180 and total price is ₹1,180. To extract GST from an inclusive price: divide the total by (1 + rate/100). ₹1,180 at 18% gives a base of ₹1,000.

What are the GST rates in India?

India has four main GST rates: 5% for essential goods, 12% for standard goods, 18% for most services and manufactured goods, and 28% for luxury and demerit goods. Some items are exempt (0%), and special rates of 0.25% and 3% apply to precious stones and gold respectively.

What is the difference between CGST, SGST, and IGST?

CGST and SGST apply to intra-state transactions, split equally between central and state governments. IGST applies to inter-state transactions, collected by the central government. For an 18% GST intra-state sale, you pay 9% CGST and 9% SGST. For inter-state, you pay 18% IGST.

When do I need to register for GST?

GST registration is mandatory when your aggregate annual turnover exceeds ₹20 lakh (₹10 lakh in special category states). For exclusive goods suppliers, the threshold is ₹40 lakh. Registration is also mandatory regardless of turnover if you make inter-state supplies or sell through e-commerce.

How do I add GST to my invoice?

A GST invoice must include your GSTIN, the buyer’s GSTIN (for B2B), item description with HSN/SAC codes, taxable value, GST rate, and CGST/SGST or IGST amounts separately. The invoice should clearly show the base price, tax amounts, and total.

What is the GST Composition Scheme?

The Composition Scheme is for small businesses with turnover below ₹1.5 crore. It offers lower tax rates (1-6%) and simplified quarterly filing. However, composition dealers cannot collect GST from customers, claim input tax credit, or make inter-state supplies.

Is GST included in MRP?

Yes, the Maximum Retail Price (MRP) printed on products is inclusive of GST. The GST component is already factored into the MRP. Retailers cannot charge above MRP. To find the pre-GST price from MRP, use the inclusive calculation: Base Price = MRP x 100 / (100 + GST Rate).

Default rates shown are illustrative. Always verify current GST rates with official notifications. Data accurate as of: March 2026