GST Calculator - Calculate GST, CGST, SGST & IGST Free GST Calculator

What is GST? Understanding Goods and Services Tax in India

Goods and Services Tax (GST) is a comprehensive, multi-stage, destination-based indirect tax levied on the supply of goods and services across India since July 1, 2017. It replaced a patchwork of cascading taxes including VAT, Service Tax, Excise Duty, CST, and others, unifying the country into a single common market.

India follows a dual GST model where both the Centre and the State simultaneously levy tax on every transaction. For intra-state supplies, CGST (Central GST) and SGST (State GST) are charged equally. For inter-state supplies, IGST (Integrated GST) is charged by the Central Government.

This free online GST calculator lets you compute the base price, GST amount, CGST, SGST, and IGST for all standard slab rates, supporting both GST-exclusive (add GST) and GST-inclusive (remove GST) calculations.

Key Features of This GST Calculator

• Add or Remove GST: Switch between GST Exclusive (add GST to base price) and GST Inclusive (extract GST from total amount) modes.
• All Standard Slab Rates: Instantly calculate for 5%, 12%, 18%, or 28% GST rates, or enter a custom rate for special categories.
• Intra-State & Inter-State: Toggle between CGST + SGST (intra-state) and IGST (inter-state) to see the correct tax split.
• Instant Results: View base amount, individual tax components (CGST, SGST, IGST), total GST, and the final total amount.
• Custom Rate Support: Enter any rate between 0.1% and 100% for goods or services that fall outside the standard slabs (e.g., 0.25% for rough diamonds, 3% for gold).

How to Calculate GST on Products — GST Formulas

How to Use This GST Calculator — Step-by-Step

1. Enter the Amount: Type the base price (if adding GST) or the total amount (if removing GST) in the Amount field.
2. Select the GST Rate: Choose from 5%, 12%, 18%, 28%, or pick "Custom" and enter your own rate.
3. Choose Calculation Type: Select "GST Exclusive (Add GST)" to add GST on top of the amount, or "GST Inclusive (Remove GST)" to extract GST from a total amount.
4. Select GST Type: Choose "Intra-State (CGST + SGST)" for transactions within the same state, or "Inter-State (IGST)" for transactions between different states.
5. Click "Calculate GST": View base amount, CGST, SGST (or IGST), total GST, and the grand total instantly.

Practical Examples — GST Calculation With Real Numbers

Example 1: Adding 18% GST to a Service (Intra-State)

• Base Amount: ₹10,000 | GST Rate: 18% | Type: Intra-State
• GST Amount = 10,000 × 18 ÷ 100 = ₹1,800
• CGST @ 9% = ₹900 | SGST @ 9% = ₹900
• Total Amount = 10,000 + 1,800 = ₹11,800

Example 2: Removing GST from a Product Price (28% GST, Inter-State)

• Total Amount (GST Inclusive): ₹25,600 | GST Rate: 28% | Type: Inter-State
• Base Price = 25,600 × 100 ÷ 128 = ₹20,000
• GST Amount = 25,600 − 20,000 = ₹5,600
• IGST @ 28% = ₹5,600
• Base Amount = ₹20,000

Example 3: 5% GST on Packaged Food (Intra-State)

• Base Amount: ₹500 | GST Rate: 5% | Type: Intra-State
• GST Amount = 500 × 5 ÷ 100 = ₹25
• CGST @ 2.5% = ₹12.50 | SGST @ 2.5% = ₹12.50
• Total Amount = 500 + 25 = ₹525

GST Rate Slabs in India — What Falls Where

Real-World Use Cases for the GST Calculator

• Invoice Preparation: Small businesses and freelancers can quickly compute the correct GST split (CGST + SGST or IGST) when preparing invoices.
• Price Verification: Consumers can verify whether the GST charged on a product or service matches the applicable slab rate.
• Reverse Calculation: Extract the base price from a GST-inclusive MRP to understand how much of the price is tax.
• Inter-State vs Intra-State Planning: Businesses can compare tax implications of buying from a local vendor versus an out-of-state supplier.
• Quotation & Tender Pricing: Calculate pre-GST and post-GST amounts for proposals, tenders, and B2B quotations.
• Personal Budgeting: Understand how much GST you pay on everyday purchases like electronics, restaurant bills, or mobile phone plans.

Understanding Your GST Results — CGST, SGST & IGST Explained

• Base Amount: The price of the good or service before any GST is applied. This is the actual cost to the seller.
• CGST (Central GST): The portion of GST that goes to the Central Government. It is equal to half the total GST rate for intra-state transactions.
• SGST (State GST): The portion of GST that goes to the State Government. Also equal to half the total GST rate for intra-state transactions.
• IGST (Integrated GST): Applied on inter-state transactions (goods moving between states). Equal to the full GST rate and collected by the Central Government, which then settles with the destination state.
• Total GST: The total tax amount — CGST + SGST for intra-state, or IGST for inter-state.
• Total Amount: The final price including GST. This is what the buyer pays.

Tips & Best Practices for GST Compliance

• Verify the HSN/SAC Code: Each product (HSN code) and service (SAC code) has a specific GST rate. Using the wrong code can lead to incorrect tax collection and compliance issues.
• Claim Input Tax Credit (ITC): Businesses can claim credit for GST paid on purchases against GST collected on sales. Ensure all purchase invoices are correctly filed in GSTR-2B.
• File Returns on Time: Late filing of GSTR-1 and GSTR-3B attracts interest (18% p.a.) and late fees. Set reminders for the 11th and 20th of each month.
• Use E-Invoicing for B2B: Businesses with turnover above ₹5 crore must generate e-invoices through the IRP portal for all B2B supplies.
• Check for Composition Scheme: Small businesses with turnover up to ₹1.5 crore (₹75 lakh for services) can opt for the composition scheme and pay GST at a flat lower rate.
• Keep Records for 6 Years: GST law requires maintaining books of accounts and invoices for at least 6 years from the due date of filing the annual return.

Common Mistakes to Avoid in GST Calculation

• Applying the Wrong Rate: Different variants of the same product can have different GST rates (e.g., footwear below ₹500 is 5%, above ₹500 is 18%). Always check the current HSN-wise rate schedule.
• Confusing Inclusive and Exclusive: MRP on products is GST-inclusive. If you add GST on top of an MRP, you will charge GST twice.
• Wrong GST Type (CGST+SGST vs IGST): Using IGST for an intra-state transaction or CGST+SGST for an inter-state transaction is a compliance error that can attract penalties.
• Not Accounting for Cess: Certain goods like luxury cars, tobacco, and aerated drinks attract additional GST Compensation Cess on top of the 28% rate. This calculator covers standard rates; add cess separately for these categories.
• Ignoring Reverse Charge Mechanism (RCM): On certain supplies (e.g., services from unregistered dealers, legal services), the buyer must pay GST under reverse charge. Ensure you account for this liability.

Frequently Asked Questions About GST Calculation

Q: What are the GST slab rates in India?

A: India has four main GST rate slabs: 5%, 12%, 18%, and 28%. Additionally, there are special rates of 0.25% for rough diamonds, 3% for gold and silver, and 0% for essential goods and services (exempt category).

Q: How do I calculate GST from a total (inclusive) amount?

A: To extract GST from a GST-inclusive amount: Base Price = Total Amount × 100 ÷ (100 + GST Rate). Then GST Amount = Total Amount − Base Price. For example, if total is ₹11,800 at 18% GST: Base = 11,800 × 100 ÷ 118 = ₹10,000, GST = ₹1,800.

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

A: CGST and SGST are levied equally on intra-state transactions (within the same state). IGST is levied on inter-state transactions (between different states) and equals the full GST rate. For example, 18% GST intra-state = 9% CGST + 9% SGST; the same 18% inter-state = 18% IGST.

Q: Is GST charged on all products and services?

A: No. Several essential goods and services are exempt from GST (0% rate), including fresh fruits, vegetables, milk, education services, and healthcare. The GST Council periodically reviews and updates the rate list.