GST Calculator - Free Online Calculator

How This GST Calculator Works

GST (Goods and Services Tax) is an indirect tax levied on the supply of goods and services in India. This calculator helps you quickly compute the GST amount and final price in two modes:

GST Exclusive (Add GST) — Enter the base amount before tax, and the calculator adds GST to show you the total price including tax.
GST Inclusive (Remove GST) — Enter the total amount including tax (like MRP), and the calculator reverse-calculates to show the base amount and GST component separately.

Select the applicable GST slab rate (0%, 5%, 12%, 18%, or 28%), and the result instantly shows the base amount, GST amount, and total — along with a pie chart breakdown. The calculator also splits the GST into CGST + SGST components for intra-state transactions.

GST Calculation Formulas

Two formulas are used depending on whether you are adding or removing GST:

Add GST: Total = Base Amount × (1 + GST Rate / 100)
Remove GST: Base Amount = Total / (1 + GST Rate / 100)

Base Amount — The price of goods or services before GST
GST Rate — The applicable tax rate (5%, 12%, 18%, or 28%)
GST Amount = Total − Base Amount
CGST = GST Amount ÷ 2 (for intra-state transactions)
SGST = GST Amount ÷ 2 (for intra-state transactions)
IGST = Full GST Amount (for inter-state transactions)

Example Calculations

Example 1: Add GST (Exclusive)

Base Amount: ₹10,000
GST Rate: 18%
GST Amount = 10,000 × 18/100 = ₹1,800
Total = 10,000 + 1,800 = ₹11,800
CGST = ₹900, SGST = ₹900

Example 2: Remove GST (Inclusive)

Total (MRP): ₹11,800
GST Rate: 18%
Base Amount = 11,800 / 1.18 = ₹10,000
GST Amount = 11,800 − 10,000 = ₹1,800

GST Slab Rates in India

India follows a multi-tier GST structure with four main rates. Here is what falls under each slab:

5% GST — Essential items like packaged food, economy-class air travel, fertilisers, small restaurants (without ITC), and transport services.
12% GST — Processed food, business-class air travel, mobile phones, sewing machines, and restaurant services in hotels with tariff above ₹7,500.
18% GST — Most goods and services fall here: electronics, IT services, financial services, restaurants in hotels with AC, telecom services, and branded garments above ₹1,000.
28% GST — Luxury and demerit goods: automobiles, consumer durables like ACs and washing machines, aerated beverages, tobacco products, cement, and five-star hotel rooms.

Some items attract an additional compensation cess on top of the 28% rate (e.g., cars, tobacco). Essential items like fresh food, milk, and healthcare are exempt (0% GST).

CGST, SGST, and IGST Explained

Understanding how GST is split between central and state governments is important for invoicing and compliance:

Intra-state supply (buyer and seller in the same state) — GST is split equally into CGST (Central GST) and SGST (State GST). For example, 18% GST = 9% CGST + 9% SGST. Both amounts appear separately on the invoice.
Inter-state supply (buyer and seller in different states) — IGST (Integrated GST) is charged at the full rate. For example, 18% IGST. The central government later settles the state's share.

The total tax amount is the same in both cases — the split only affects how the tax is reported and remitted. This calculator shows the total GST amount; for CGST/SGST split, divide the GST amount by 2.

Common Use Cases

Invoice Preparation — Calculate exact GST amounts for invoices. Enter the base price of goods or services and get the GST and total amounts to include on your bill.
MRP Verification — Check the pre-tax price of any product by entering its MRP and selecting "Remove GST" to see the actual base cost and tax component.
Price Comparison — Compare products across different GST slabs by calculating the effective pre-tax price to understand the true cost difference.
Freelancer Billing — If you are a consultant or freelancer charging 18% GST, quickly compute the total amount to invoice your client including tax.
Input Tax Credit Planning — Businesses can calculate the GST paid on purchases to estimate the ITC available against their output tax liability.
Budget Estimation — When planning purchases for your business or home, factor in GST to get accurate total cost estimates before committing.

Frequently Asked Questions

How is GST calculated?

GST is calculated by multiplying the base amount by the applicable GST rate percentage and dividing by 100. For example, if the base amount is ₹1,000 and the GST rate is 18%, the GST amount is ₹180 and the total becomes ₹1,180. To remove GST from an inclusive amount, divide the total by (1 + rate/100) to get the base amount.

What are the GST slab rates in India?

India has four main GST slab rates: 5%, 12%, 18%, and 28%. Essential items like food grains attract 0% or 5%, standard goods and services fall under 12% or 18%, and luxury and demerit goods attract 28%. Some items also have an additional compensation cess on top of the 28% rate.

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

CGST (Central GST) and SGST (State GST) are levied equally on intra-state transactions. For example, 18% GST on an intra-state sale means 9% CGST + 9% SGST. IGST (Integrated GST) is levied on inter-state transactions and equals the full GST rate (e.g., 18% IGST). The total tax burden remains the same regardless of whether it is intra-state or inter-state.

How to calculate GST from MRP?

MRP is the GST-inclusive price. To extract GST from MRP, use the formula: Base Amount = MRP / (1 + GST Rate/100). The GST component is then MRP minus the base amount. For example, if MRP is ₹1,180 at 18% GST, the base amount = 1180 / 1.18 = ₹1,000, and GST = ₹180. Use the "Remove GST" mode in this calculator for instant results.

Is GST applicable on all goods and services?

No, several items are exempt from GST. These include fresh fruits and vegetables, milk, eggs, unprocessed food grains, healthcare services, and educational services provided by recognized institutions. Petroleum products like petrol, diesel, and natural gas are also currently outside the GST ambit and are taxed under the old excise and VAT regime.

What is reverse charge mechanism?

Under the reverse charge mechanism (RCM), the recipient of goods or services pays the GST directly to the government instead of the supplier. This applies to specified goods and services listed under Section 9(3) and 9(4) of the CGST Act, such as services received from an advocate, goods transport agency, or from an unregistered dealer exceeding prescribed limits.

How does input tax credit work?

Input Tax Credit (ITC) allows businesses to claim credit for GST paid on purchases against the GST collected on sales. For example, if you collect ₹18,000 GST on sales and paid ₹12,000 GST on purchases, you only need to remit ₹6,000 to the government. ITC is available only for GST-registered businesses and requires valid tax invoices from suppliers.

Are there any GST-exempt items?

Yes, many essential items are GST-exempt (0% rate). These include fresh milk, fruits, vegetables, bread, salt, natural honey, unprocessed cereals, and live animals. Services like healthcare by clinical establishments, education by recognized institutions, and public transportation are also exempt from GST. The full list is maintained in GST exemption notifications.

Important Notes

This GST calculator provides estimates for quick reference. For official tax filing and compliance, use the GST portal (gst.gov.in) and consult a chartered accountant.

GST rates are revised periodically by the GST Council. Always verify the current applicable rate for your specific goods or services before preparing invoices or making pricing decisions.

This calculator does not account for compensation cess, which applies to certain luxury and demerit goods on top of the 28% GST slab. Check the HSN/SAC code for your product or service for the exact rate.

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