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GST Calculator

Add GST to a price or take it out of a GST-inclusive price, for one item or a whole bill, with the CGST, SGST and IGST split.

Total amount with GST
₹1,180.00

GST is ₹180.00 on a taxable value of ₹1,000.00

Taxable value
₹1,000.00
Total GST
₹180.00
CGST + SGST
₹90.00 + ₹90.00
Invoice total
₹1,180.00

Summary by GST rate

The taxable value and tax at each rate, ready to copy into an invoice or a return.

GST rateTaxable valueCGST + SGSTTotal
18%₹1,000.00₹180.00₹1,180.00
Total₹1,000.00₹180.00₹1,180.00

This calculator does arithmetic only. GST rates are set by the GST Council and change by notification, so confirm the rate that applies to your goods or services. It is not tax advice.

How to use this GST calculator

  1. Choose "Add GST" if your amounts are before tax, or "Remove GST" if they already include it.
  2. Enter the amount and the GST rate for each line. Start typing in the rate box to pick a common rate, or type your own.
  3. Turn on "Sale to another state" if the supply is between states, so the tax shows as IGST.
  4. Read the taxable value, the GST and the total, plus the split by rate.

The two formulas

You haveFormulaExample at 18%
Price before GSTGST = price x rate / 100. Total = price + GST.₹1,000 gives GST ₹180 and a total of ₹1,180
Price including GSTPrice before GST = total / (1 + rate / 100). GST = total - price before GST.₹1,180 gives ₹1,000 before GST and ₹180 GST

CGST and SGST, or IGST

Whether a sale is treated as within a state or between states depends on the place of supply. Within a state, an 18% GST is split into 9% CGST and 9% SGST, so a ₹180 tax shows as ₹90 and ₹90. Between states the same ₹180 is charged as IGST. The total tax is identical either way; only the head it is booked under changes.

GST rates

The GST Council sets rates by item, and they change by notification. From 22 September 2025 most goods and services moved into 5% and 18% slabs, with a higher 40% rate on a small list of items and special rates such as 3% and 0.25%. The rate box lets you type any rate, so you are not tied to the common ones, and it is worth confirming the rate for your specific item before you invoice.

From calculation to invoice

Once you know the figures, put them on a proper bill with the invoice generator, which supports a tax label and rate. For a simple discount followed by tax, the discount and sales tax calculator is a quicker route. This tool does the arithmetic only: it does not register you for GST, choose your rate or file returns.

Frequently Asked Questions (FAQ)

Multiply the amount by the GST rate and divide by 100. GST on ₹1,000 at 18% is ₹180, so the invoice total is ₹1,180. Choose "Add GST" in this calculator and enter the pre-tax amount.
Divide the GST-inclusive price by (1 + rate/100). For ₹1,180 at 18%, that is 1,180 / 1.18 = ₹1,000, so ₹180 of the price is GST. Choose "Remove GST" and enter the inclusive amount. Note that it is not 18% of 1,180: taking a percentage off the inclusive price gives the wrong answer.
For a sale within one state, the GST is split equally between the Centre (CGST) and the state (SGST or UTGST): 9% + 9% for an 18% rate. For a sale between states, the whole amount is charged as IGST. Switch on "Sale to another state" to see the IGST view.
The rate depends on what you are selling and is set by the GST Council. Since the changes effective from 22 September 2025, most goods and services fall in the 5% and 18% slabs, with 40% on a few items and special rates such as 3% for gold and 0.25% for rough diamonds. Rates are updated by notification, so confirm the rate for your item, and use the rate printed on the invoice when checking a bill.
Yes. Add up to 8 lines, each with its own amount and rate. The calculator totals them and shows the taxable value and GST for each rate, which is the summary you need when filling in an invoice or a return.
No. It only does the arithmetic. Whether you must register, charge GST or claim input tax credit depends on your turnover, what you supply and where, so check with the GST portal or an accountant.
The calculator works to the paisa and shows amounts rounded to whole rupees or two decimals. On an invoice, round each line the way your billing software does, since small differences can appear between line-level and invoice-level rounding.
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