About this gst calculator
Calculate Goods and Services Tax the way Indian invoices need it, either by adding GST on top of a base price or by extracting how much of a GST-inclusive total is tax. Choose your direction, enter the amount and the applicable rate, such as the common 5%, 12%, 18%, or 28% slabs, and see the base price, GST amount, an even CGST and SGST split, and the total. This suits shopkeepers, freelancers, and shoppers who want to check an invoice or quote without doing the arithmetic by hand.
How it works
Adding GST: GST amount equals the base price multiplied by the rate divided by 100, and the total is the base price plus that GST amount. Extracting GST: the base price equals the total divided by one plus the rate divided by 100, and the GST amount is the total minus that base price. For an intra-state sale, CGST and SGST each take half of the GST amount.
Try these examples
Add 18% GST to ₹1,000
GST ₹180 · Total ₹1,180
Extract 18% GST from a ₹1,180 total
Base price ₹1,000 · GST ₹180
Limitations & privacy
This calculates standard single-rate GST only; it does not handle mixed-rate invoices, GST composition scheme rules, reverse charge, or exemptions. Confirm the applicable rate and scheme for your specific goods or services.
Inputs and results stay in this browser. Only tool identifiers are stored for your recently used tools. You can clear that history from the directory.
A few good questions
What's the difference between CGST and SGST?
For a sale within the same state, GST splits evenly into Central GST and State GST. For an inter-state sale, the full amount is instead charged as Integrated GST (IGST), which this tool reports as the combined GST amount.
Which mode should I use for a shop receipt?
If the listed price already includes tax, use "Extract GST from a total price." If you're building a quote from a pre-tax price, use "Add GST to a base price."
Can I use a custom GST rate?
Yes, enter any percentage; the common slabs of 5, 12, 18, and 28 are just typical starting points.
Updated September 19, 2026