Use this free GST calculator to add or remove GST in seconds. Enter an amount, pick the GST rate, and the tool shows the base value, the GST, and the total, with the CGST, SGST and IGST split worked out for you. Everything runs in your browser, with no signup and nothing uploaded.
How the GST calculator works
There are two everyday questions this GST calculator answers. To add GST, it takes your base amount and adds the tax: GST equals amount times rate, and the total is the amount plus that GST. To remove GST, which is a reverse GST calculation, it treats your figure as GST inclusive and works backwards, so the base equals the total divided by one plus the rate, and the GST is whatever is left.
For example, on a base of 1,000 rupees at 18 percent, the GST is 180 rupees and the total is 1,180 rupees. Start from a GST inclusive 1,180 rupees and the calculator returns the same 1,000 rupee base and 180 rupee GST.
CGST, SGST and IGST explained
Indian GST is split by where the supply happens. For a sale within the same state, called intra-state, the GST is shared equally as CGST and SGST, so 18 percent becomes 9 percent CGST and 9 percent SGST. For a sale between states, called inter-state, the whole amount is charged as IGST. This calculator switches the split automatically when you choose intra-state or inter-state.
GST rates in India and what falls under each
Since the GST 2.0 reform on 22 September 2025, India uses three main GST rates, 5 percent, 18 percent and 40 percent, alongside 0 percent on many essentials. The older 12 and 28 percent slabs were folded into these. The calculator defaults to 18 percent, the standard rate, and you can still type any custom rate, since a few items sit at special rates. Always confirm the current rate for your specific item on the official GST portal at cbic.gov.in.
| Rate | Typical category | Examples |
|---|---|---|
| 0% | Essentials | Fresh produce, milk, bread and unpacked food, sanitary napkins, plus education and healthcare services |
| 5% | Everyday items | Hair oil, soap, shampoo and toothpaste, packaged dairy like butter and ghee, common medicines and diagnostic kits |
| 18% | Standard rate | Most goods and services, including small cars, televisions, air conditioners and other electronics, and professional and IT services |
| 40% | Luxury and sin | Large cars and SUVs, aerated and carbonated drinks, tobacco and pan masala, motorcycles above 350cc, yachts and private aircraft, and betting, casinos and online gaming |
What changed in GST 2.0
Before 22 September 2025 there were five slabs: 0, 5, 12, 18 and 28 percent. Most items that were at 12 percent, such as packaged dairy and many processed foods, moved down to 5 percent. Most items that were at 28 percent, such as televisions, air conditioners and small cars, moved down to 18 percent. A new 40 percent rate took over from the old 28 percent plus cess on luxury and sin goods like large cars and SUVs, aerated drinks and tobacco. In short, many everyday items got cheaper, while a few luxury and sin items moved up.
If you raise or receive supplier bills, our accounts payable template helps you track them, and the TDS rate calculator covers tax deducted at source on the same invoices. Freelancers on presumptive tax can also use the 44ADA presumptive tax calculator.
Automate your GST reconciliation
Working out GST on one amount is the easy part. Reconciling it every month is where the time goes. Our app at app.reconscribe.com handles that for you. It matches your purchase books against your GSTR-2B, flags mismatches and missing invoices, and tracks the input tax credit you can actually claim, including credit that carries forward to later months. The same app also automates accounts payable, reading supplier invoices from your inbox, pulling out the line items and tax, and posting them straight into your accounting system. If you lose hours each month to 2B matching or invoice entry, see what reconscribe can take off your plate.
Frequently Asked Questions
How is GST calculated on an amount?
Multiply the base amount by the GST rate to get the GST, then add it to the base for the total. For 18 percent GST on 1,000 rupees, the GST is 180 rupees and the total is 1,180 rupees.
How do I remove GST from a total?
Divide the GST inclusive total by one plus the rate. For an 18 percent inclusive total of 1,180 rupees, the base is 1,180 divided by 1.18, which is 1,000 rupees, and the GST is 180 rupees.
What is the difference between CGST, SGST and IGST?
CGST and SGST apply together on sales within a state and split the GST equally between the centre and the state. IGST applies on sales between states and is collected as a single amount. The total tax is the same either way.
What are the GST rates in India?
Since the GST 2.0 reform of September 2025, the main slabs are 5, 18 and 40 percent, with 0 percent on many essentials. The 12 and 28 percent slabs were merged into these. Check the official rate for your item at cbic.gov.in.
Need to raise GST-compliant invoices, not just calculate the tax? Try our free GST invoice generator.