Free tool · GST 2.0
GST calculator, with the split built in.
Add or remove GST, see CGST/SGST or IGST, and get an invoice-ready total. Built for Tamil Nadu businesses — and anyone invoicing from here.
Rates and content reviewed: 26 October 2026
Live calculator
GST 2.0 · reviewed 26 Oct 2026
Tell us the amount. We'll do the split.
Choose a rate and where the buyer is. The estimate updates as you type.
Your estimate
Live
Intellitax Solutions
GST estimate · 26 October 2026
GST estimateAdd GST
Estimate only
Total invoice value
₹0.00
Plus GST
Taxable value₹0.00
CGST @ 9%₹0.00
SGST @ 9%₹0.00
IGST @ 18%₹0.00
Total GST₹0.00
Round off₹0.00
₹0.00 + ₹0.00 = ₹0.00
Within Tamil Nadu
18%
Rates reviewed 26 Oct 2026
Estimate only. Verify the HSN/SAC classification and the GST rate in force on the invoice date. This is not a tax invoice.
Calculated in your browser. No amounts are stored.
Rate impact
The same amount at different rates.
Using ₹10,000.00 as the taxable value.
The comparison uses the same amount and supply type. It does not decide which rate applies to your goods or services.
The math
Three formulas. No spreadsheet.
The calculator works in paise, then formats the result to two decimals. That keeps the taxable value, the tax and the total reconciled.
Start with the taxable value.
GST = amount × rate ÷ 100
At 18%, ₹10,000 becomes ₹1,800 GST and a total of ₹11,800.
₹10,000 + ₹1,800 = ₹11,800Start with the inclusive total.
Taxable value = total × 100 ÷ (100 + rate)
At 18%, ₹11,800 becomes a taxable value of ₹10,000 and GST of ₹1,800.
₹11,800 − ₹1,800 = ₹10,000Show it the way the invoice needs it.
CGST = SGST = GST ÷ 2 · IGST = GST
Within Tamil Nadu, ₹1,800 becomes ₹900 CGST + ₹900 SGST. For another state, it is ₹1,800 IGST.
₹900 + ₹900 = ₹1,800When the tax has an odd number of paise, the extra paise is allocated to one half of the CGST/SGST split so the two halves still add back to the total GST. The optional rounding setting affects only the final invoice total.
GST 2.0
Current rates, clearly labelled.
The main structure effective 22 September 2025 is 0%, 5%, 18% and 40%, with special rates retained for specified goods.
Nil-rated or exempt supplies, subject to the notification and conditions.
The lower standard rate for specified goods and services.
The main standard rate for most goods and services.
For specified goods and services notified at the higher rate.
Special rates
Some goods sit outside the main slabs.
0.25% for specified rough diamonds and precious stones, and 3% for specified gold, silver, platinum and jewellery. Conditions apply. Use the calculator's special-rate menu for these.
Rates reviewed 26 October 2026. GST depends on the HSN/SAC classification and the notification in force on the invoice date. For invoices dated before 22 September 2025, use the custom rate for 12% or 28% where applicable. This page is an estimate, not a ruling.
Place of supply
CGST, SGST or IGST?
For a Tamil Nadu seller, the buyer's location decides how the tax is shown on the invoice.
Within Tamil Nadu
The GST is split equally between CGST and SGST. On a ₹10,000 sale at 18%, that is ₹900 CGST + ₹900 SGST.
Other state / UT
The full GST is charged as IGST. On the same ₹10,000 sale at 18%, that is ₹1,800 IGST.
Union Territory supplies can use CGST + UTGST where the supplier and place of supply are in the same UT. This calculator is set up for a Tamil Nadu seller; if your registration is elsewhere, confirm the treatment with your accountant. Exports and SEZ supplies can be zero-rated with conditions, which this calculator does not determine.
Questions
Before you invoice.
The calculator gives you the arithmetic. The rate still depends on what you sell and where it is supplied.
Ask about a rateFAQs last reviewed: 26 October 2026
How do I add GST to an amount?
Multiply the taxable value by the GST rate and divide by 100, then add the tax to the taxable value. For example, ₹10,000 at 18% gives ₹1,800 GST and a total of ₹11,800.
How do I remove GST from an inclusive total?
Multiply the GST-inclusive total by 100 and divide by 100 plus the rate. For example, ₹11,800 at 18% gives a taxable value of ₹10,000 and GST of ₹1,800.
What is the difference between CGST, SGST and IGST?
For an intra-state supply, GST is split equally between CGST and SGST. For an inter-state supply, the full GST is charged as IGST. The buyer's location and the place of supply determine which treatment applies.
Which GST rate should I use?
The rate depends on the HSN or SAC classification and the notification in force on the invoice date. The main GST 2.0 structure is 0%, 5%, 18% and 40%, with special rates such as 0.25% and 3% for specified goods. Confirm the classification before invoicing.
Is this calculator updated for GST 2.0?
Yes. The calculator was reviewed on 26 October 2026 and uses the 0%, 5%, 18% and 40% structure effective from 22 September 2025, plus special rates and a custom rate for historical or notified cases.
Can I use this calculation as a tax invoice?
No. It is an estimate, not a tax invoice or a ruling. A valid tax invoice also needs the supplier and recipient details, GSTIN, invoice number and date, HSN or SAC, place of supply and the other particulars required by law.
Are my amounts stored?
No. The calculation runs in your browser. The site does not save amounts in local storage, send them to a server or require a login. Copy and WhatsApp actions only use the summary when you choose them.
Not sure which rate applies to your invoice?
Send the amount, the HSN/SAC code and the place of supply. We'll help you check the rate before the invoice goes out.