GST Calculator
Calculate GST inclusive & exclusive amounts.
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Adjust the inputs on the left to see your gst amount.
The confusion this clears up
Most GST mistakes come from one question: is the price you are looking at inclusive of tax or not? A shopkeeper quoting 1,180 for something might mean 1,180 plus GST, or 1,180 with GST already baked in. Those are two different numbers, and getting them mixed up wrecks an invoice.
This calculator handles both directions. Give it an amount and a GST rate, and it can add GST on top (exclusive) or pull GST out of a tax-included price (inclusive). It also splits the tax into CGST and SGST for you, which is exactly what a proper invoice needs.
Adding GST versus extracting it
To add GST, the maths is simple. GST amount = price x rate divided by 100. So 1,000 at 18 percent adds 180, giving 1,180.
To extract GST from an inclusive price, you reverse it. GST = inclusive price x rate divided by (100 plus rate). On that same 1,180 at 18 percent, the GST inside is 1,180 x 18 / 118, which is 180, leaving a base of 1,000. People who simply take 18 percent of 1,180 get 212.40, and that small error compounds across a month of invoices.
A worked invoice
You run a design studio in Bengaluru and bill a client 50,000 plus GST at 18 percent. Tax comes to 9,000, so the invoice total is 59,000. Because the client is in Karnataka like you, that 9,000 splits into 4,500 CGST and 4,500 SGST. Had the client been in Maharashtra, the same 9,000 would be a single IGST line instead.
That intra-state versus inter-state split trips up new freelancers constantly, so it is worth saying plainly: same state means CGST plus SGST, different states means IGST.
Rates and rules worth knowing
GST in India runs across a few slabs, commonly 5, 12, 18, and 28 percent, with some items at 0. A handful of points that save headaches:
- Match the rate to the correct HSN or SAC code for your product or service. Guessing the slab is how notices start.
- If your turnover crosses the registration threshold, charging and filing GST is not optional.
- Input tax credit lets you offset GST you paid on business purchases against GST you collect. Keep clean records, because credit without matching invoices does not survive scrutiny.
Use this tool for quick quotes and reconciliations, but lean on a tax professional for filings and edge cases. Slabs and rules get revised, so confirm the current rate for your category before you raise a bill.
GST Calculator — frequently asked questions
How do I remove GST from a total price?
Use GST = total x rate divided by (100 plus rate). For a 1,180 price that already includes 18 percent GST, that is 1,180 x 18 / 118, which equals 180. The base price is 1,000. Taking a flat 18 percent of 1,180 is the common mistake and gives a wrong, higher figure that will not match your books.
What is the difference between CGST, SGST, and IGST?
For a sale within the same state, GST splits equally into CGST (central) and SGST (state). For a sale between two states, it becomes a single IGST charge instead. The total tax is the same either way. The split only decides which government gets the share, but your invoice must show the right one.
How do I add GST to a price?
Multiply the base price by the rate and divide by 100 to get the tax, then add it on. So 1,000 at 18 percent adds 180, making 1,180. For an intra-state sale, show that 180 as 90 CGST and 90 SGST on the invoice. The calculator does this split automatically once you pick the rate.
Which GST rate applies to my product?
Rates depend on the item and its HSN or SAC code, and they sit in slabs such as 5, 12, 18, and 28 percent, with some goods at 0. You cannot guess the slab safely. Look up the official code for your specific product or service, since charging the wrong rate can trigger a tax notice later.
Do I need GST registration for a small business?
Registration becomes mandatory once your turnover crosses the threshold set for your state and business type, and it is also required for certain inter-state and online sellers regardless of turnover. Below the limit it is optional, though some small businesses register voluntarily to claim input tax credit. Check the current threshold for your category before deciding.
What is input tax credit in GST?
Input tax credit lets a business reduce the GST it owes on sales by the GST it already paid on business purchases. So if you collected 9,000 and paid 2,000 on inputs, you remit 7,000. The credit only holds when your purchase invoices match what suppliers filed, so accurate records matter a great deal.
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Results from this calculator are estimates for informational use only — not financial, medical, or professional advice. Read our full disclaimer before acting on any number you see here.