GST Calculator
Add or remove GST at 5%, 12%, 18% and 28% slabs instantly.
What is the GST Calculator?
A GST calculator works out Goods and Services Tax on any amount so you do not have to. You can add GST to a base price to get the final amount, or remove GST from a GST-inclusive price to find the original value and the tax portion. It supports the common Indian slabs — 5%, 12%, 18% and 28% — and splits the total into CGST and SGST, which is what most invoices need. Shop owners, freelancers, students and anyone dealing with bills or quotes can get accurate figures in seconds.
How to use the GST Calculator
- Enter your amount.
- Select the GST rate — 5%, 12%, 18% or 28%.
- Choose whether to add GST or remove it from a GST-inclusive price.
- View the GST amount, the CGST and SGST split, and the final price.
Why use Quably's GST Calculator?
- Add or remove GST
- Splits CGST and SGST automatically
- All standard slabs supported
- Accurate results instantly
- Free, no sign-up
GST Calculator formula
Adding GST: GST amount = Price × (GST rate ÷ 100), and Final price = Price + GST amount. Removing GST from an inclusive price: Base = Inclusive price ÷ (1 + rate ÷ 100). CGST and SGST are each half of the GST amount.
Examples
Adding 18% GST
On ₹1,000 the GST is ₹180 (CGST ₹90 + SGST ₹90), so the final price is ₹1,180.
Removing 18% GST
A GST-inclusive price of ₹1,180 works back to a base of ₹1,000 and ₹180 GST.
Frequently asked questions
How do I calculate GST?
Multiply the amount by the GST rate divided by 100. For 18% on ₹1,000 that is 1,000 × 0.18 = ₹180.
How do I find the GST-inclusive price?
Add the GST amount to the base price. The tool shows the final inclusive price for you.
How is CGST calculated?
For an intra-state sale, CGST is half of the total GST — so 9% when the GST rate is 18%.
How is SGST calculated?
SGST is the other half of the GST — also 9% when the rate is 18%. CGST and SGST together make up the full GST.
Can I use this GST calculator for my business?
Yes, it works for quotes, invoices and quick checks. For filing, always confirm figures against your accounting records.
Is the Quably GST calculator free?
Yes, it is completely free and needs no sign-up.