Free Tool
GST Calculator
Calculate GST amount, base value, and total invoice value instantly — for GST-inclusive or GST-exclusive amounts.
GST Calculator
How It Works
Understanding GST calculation
Under India's GST regime, tax is applied at a fixed percentage of a good or service's value. If your amount excludes GST, the tax is added on top: GST Amount = Base Amount × GST Rate ÷ 100, and Total = Base Amount + GST Amount. If your amount already includes GST, the base value is calculated by working backward: Base Amount = Total ÷ (1 + GST Rate ÷ 100).
For transactions within the same state, this GST amount is typically split equally into CGST and SGST. For inter-state transactions, the full amount is charged as IGST instead.
FAQ
Frequently asked questions
What is GST?
GST (Goods and Services Tax) is a single, unified indirect tax levied on the supply of goods and services in India, replacing multiple earlier taxes like VAT, service tax, and excise duty.
How is GST calculated?
GST is calculated by applying the applicable GST rate (e.g., 5%, 12%, 18%, or 28%) to the base (taxable) value of a good or service. For an amount excluding GST, GST Amount = Base Amount × (GST Rate / 100).
What's the difference between GST-inclusive and GST-exclusive amounts?
A GST-exclusive amount doesn't yet include tax — GST is added on top. A GST-inclusive amount already has GST built in, so the base amount is calculated by working backward from the total.
What are CGST and SGST?
For transactions within the same state, GST is split equally into CGST (Central GST) and SGST (State GST) — each typically half of the total GST rate. For inter-state transactions, IGST (Integrated GST) applies instead, equal to the full GST rate.
What are the standard GST rates in India?
Common GST slabs in India are 0%, 5%, 12%, 18%, and 28%, depending on the category of goods or services.
Is this GST calculator free to use?
Yes, this calculator is completely free, requires no sign-up, and can be used as many times as you need.
Can I use this to calculate GST for an invoice?
Yes — enter your invoice amount and applicable GST rate to instantly see the base amount, GST amount, and total payable.
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