Enter amount and GST rate, select calculation type, then click "Calculate GST".
Example: $100 + 18% GST = $118 total, or $118 inclusive → $100 base + $18 GST
The GST Calculator helps you compute the Goods and Services Tax (GST) on any product or service. Whether you need to add GST to a net price (exclusive) or extract GST from a gross price (inclusive), this GST tax calculator provides instant results. It supports any currency and any GST rate, making it perfect for businesses, accountants, and consumers worldwide.
GST Formulas
GST (exclusive) = Amount × (Rate / 100)
Total (exclusive) = Amount + GST
Original (inclusive) = Total / (1 + Rate/100)
GST (inclusive) = Total − Original
For example, if you have a product priced at $100 excluding 18% GST, the GST amount is $18 and the total is $118. If you have a total of $118 that already includes 18% GST, the original amount is $100 and the GST is $18. Our calculator handles both scenarios.
Applications
Business invoicing: Calculate GST to charge customers correctly.
Tax filing: Determine GST payable or input tax credit.
Price comparison: Compare pre‑tax prices across different GST rates.
Budgeting: Understand how much tax you actually pay on purchases.
Understanding GST Exclusive vs. Inclusive
Exclusive GST: Used when the quoted price does not include tax. Common in B2B transactions and wholesale pricing. You add GST on top.
Inclusive GST: Used when the quoted price already includes tax. Common in retail and consumer pricing. You extract the GST component from the total.
GST Rates Around the World
India: 5%, 12%, 18%, 28% (plus cess on luxury goods)
Australia: 10% GST
Canada: 5% GST (plus provincial sales taxes)
United Kingdom: 20% VAT (similar to GST)
Singapore: 8% GST (rising to 9% in 2024)
Malaysia: 6% SST (replaced GST)
New Zealand: 15% GST
How to Calculate GST Backwards (Reverse Charge)
If you know the total amount including GST and want to find the original price and the GST amount, divide the total by (1 + GST rate/100). For example, a ₹118 total with 18% GST: ₹118 / 1.18 = ₹100 (original). Then subtract: ₹118 − ₹100 = ₹18 GST. This is useful for claiming input tax credit or understanding actual costs.
Common Mistakes When Calculating GST
Using the wrong rate: Different products have different GST rates (e.g., essential vs. luxury).
Confusing exclusive vs. inclusive: Adding GST to an already inclusive price double‑counts tax.
Rounding errors: Always use at least two decimal places for accurate tax filing.
Forgetting to add GST on shipping/charges: Delivery fees are often taxable.
Input Tax Credit (ITC) – How Businesses Benefit
Businesses registered for GST can claim credit for the GST they pay on purchases (inputs). This reduces the net GST payable. For example, if you collect $100 GST from customers but paid $40 GST on supplies, you only remit $60 to the government. Our calculator helps compute GST on both sales and purchases for ITC calculation.
Use this GST calculator for all your tax calculations. Bookmark it to quickly determine GST amounts for invoices, purchase orders, or personal budgeting. Whether you are a business owner, accountant, or consumer, this tool simplifies GST computation.
GST (Goods and Services Tax) is a value-added tax levied on most goods and services sold for domestic consumption. It is paid by consumers but remitted to the government by businesses.
What is the difference between exclusive and inclusive GST?
Exclusive GST means the price does not include tax – GST is added on top. Inclusive GST means the price already includes the tax – GST is extracted from the total.
How do I calculate GST backwards?
If you have a price that already includes GST, divide by (1 + GST rate/100) to get the original amount. The GST amount is the total minus the original.
What are common GST rates?
Rates vary by country: India has 5%, 12%, 18%, 28%; Australia has 10%; Canada has 5% GST + provincial taxes; UK has 20% VAT (similar to GST).