GST Calculator
Calculate GST-inclusive or GST-exclusive amounts instantly.
How to use this calculator
Use Add GST when you have a base price and want to know the final price after tax. Use Remove GST when you have a final price that already includes GST and want to find the original base amount. Select the applicable GST slab and enter your amount to see the breakdown.
What is GST?
GST (Goods and Services Tax) is India's unified indirect tax, charged on the sale of most goods and services and collected by the seller on behalf of the government. Since the GST 2.0 reform took effect on September 22, 2025, the four-slab system (5/12/18/28%) was simplified into 0%, 5%, 18%, and a 40% de-merit rate for select luxury and sin goods. A wrong rate or a wrong direction puts the wrong tax on the invoice, and the same wrong figure then goes into your GST return.
How GST is calculated
To add GST to a base (exclusive) amount: GST Amount = Base × (Rate ÷ 100), then Final Price = Base + GST Amount. To remove GST from a price that already includes it, you can't simply multiply by the rate again — instead, Base Amount = Final Price ÷ (1 + Rate ÷ 100), and the GST amount is the difference between the two.
Worked example
A product priced at ₹1,000 (exclusive of GST) at the standard 18% rate: GST Amount = 1,000 × 0.18 = ₹180, so the final price is ₹1,180. Now take that same ₹1,180 as an inclusive price instead — removing GST gives 1,180 ÷ 1.18 = ₹1,000 base and ₹180 GST, the exact reverse. Note that 1,180 × 0.18 = ₹212.40, not ₹180 — multiplying an inclusive price directly by the rate is the mistake to avoid.
Frequently Asked Questions
Which GST rate applies to my product or service?
The rate is determined by the specific HSN (goods) or SAC (services) code, not a general category guess. After the GST 2.0 reform in September 2025, most everyday goods and services fall under 5% or 18%, with 40% reserved for select luxury and sin goods. Look the code up with the HSN/SAC search on the GST portal (services.gst.gov.in) to find the rate notified for it.
What is the difference between GST-inclusive and GST-exclusive pricing?
An exclusive price has GST added on top to get the final price a customer pays. An inclusive price already contains the GST, so the tax is taken out of it, not added. At 18%, the GST inside ₹5,900 is ₹5,900 × 18 ÷ 118 = ₹900, on a base of ₹5,000. Multiplying ₹5,900 by 18% gives ₹1,062, which is tax on the tax-inclusive figure and overstates it by ₹162.
How do I calculate GST when there is a discount?
Apply the discount to the base amount first, then calculate GST on the discounted figure — never calculate GST on the original price and subtract a discount afterward, since that overstates the tax owed.
Can this calculator handle CGST and SGST split separately?
This calculator shows the total GST amount only. For intra-state transactions, that total is split equally between CGST and SGST (UTGST in a union territory) (e.g. 18% GST becomes 9% CGST + 9% SGST); for inter-state transactions, the full amount is charged as IGST instead. Divide the GST Amount shown here by two if you need the CGST/SGST breakdown.
Related Tools
Related Blog Posts
How to Calculate GST in India — Step by Step
The two GST formulas (adding tax and removing it), how the amount splits into CGST + SGST or IGST, and worked examples for discounts and invoices that mix tax rates.
Read moreProfit Margin vs Markup: Pricing, GST and Discounts Worked Out
The markup-to-margin conversion table, pricing a ₹600 product for a 40% margin (₹1,000, not ₹840), why margin calculated on a GST-inclusive price is wrong, and why a 20% discount means selling twice as many units.
Read moreHow to Calculate Home Loan EMI and Reduce Total Interest
A worked ₹40 lakh example showing where your EMI goes, and what a shorter tenure, a lower rate, and prepayments each save in rupees.
Read more