GST Calculator
Two jobs every shopkeeper, freelancer and buyer in India does again and again: add GST to a price before billing, and pull the GST back out of an MRP to see the real base price. This page does both, and breaks the tax into CGST, SGST and IGST so the numbers on your bill finally make sense.
Your amount
Your result
For one bill you charge either CGST + SGST (sale inside one state) or IGST (sale to another state) — the GST amount is the same; only the split changes.
Please note: this calculator gives quick estimates for quotations and bill-checking — it is not tax advice. GST rates, exemptions and rules change through official notifications; confirm the rate for your goods or services with your CA or from official GST sources before raising an invoice.
What is GST, in simple words?
GST — Goods and Services Tax — is the tax added when most things are sold in India. Before GST, a single sale could pass through excise, VAT and service tax one after another. GST folded those into one tax with one idea at its centre: the tax is charged at every stage of sale, but a registered business claims back the GST it already paid on its purchases (input tax credit), so in the end the tax effectively falls on the final customer.
For everyday maths, though, you only need two moves: adding the tax on top of a price, and separating it out of a price that already contains it. That is all this page does — no sign-up, and your amounts stay in your browser.
CGST, SGST and IGST — what is the difference?
- CGST is the central government's share, and SGST is the state government's share. On a sale within one state, the GST splits exactly in half between them: at 18%, that is 9% CGST + 9% SGST.
- IGST applies when a sale crosses a state border. The whole tax is charged as IGST (18% in the same example) and later settled between governments.
- For the buyer and seller, the total tax is identical either way — only the labels on the invoice change.
The two formulas
Adding GST: Total = Base + (Base × Rate ÷ 100)
Removing GST: Base = Inclusive amount ÷ (1 + Rate ÷ 100)
The second formula is where most people slip. To find the base inside an MRP you divide — you do not subtract the percentage from the MRP. Subtracting 18% from ₹11,800 gives ₹9,676, which is wrong; dividing by 1.18 gives the correct ₹10,000.
A worked example
A freelancer bills a client ₹10,000 plus GST at 18%:
- GST amount: ₹1,800
- Client in the same state: CGST ₹900 + SGST ₹900
- Client in another state: IGST ₹1,800
- Invoice total: ₹11,800
Now run it backwards. A phone is priced at ₹11,800 MRP (GST included). Switch this calculator to “Remove GST” and the base price is ₹10,000 with ₹1,800 of tax inside the MRP. Small amounts work the same way: ₹999 at 5% carries ₹49.95 of GST, for a total of ₹1,048.95.
How to use this calculator
- Choose “Add GST” if your amount is the price before tax, or “Remove GST” if it already includes tax, like an MRP.
- Type the amount and pick the rate — or choose “Custom rate” for rates like 0.1% or 3% used for special categories.
- Read the base amount and GST, then use the CGST + SGST pair for a same-state bill or the IGST figure for an out-of-state bill.
- Use “Copy result” to paste the breakup into a quotation or message.
Frequently asked questions
What is GST?
GST (Goods and Services Tax) is India's main indirect tax, charged when goods or services are sold. It replaced a chain of older taxes like VAT, service tax and excise. The seller collects GST from the buyer and pays it to the government, and registered businesses usually claim credit for the GST they paid on their own purchases.
Should I look at CGST + SGST, or IGST?
It depends on where the buyer and seller are. For a sale within the same state, the tax splits into CGST (central share) and SGST (state share) — half each. For a sale across state lines, the full amount is charged as IGST instead. You pay one or the other, never both; the total GST is the same either way.
How do I remove GST from an MRP or invoice total?
Divide the inclusive amount by (1 + rate ÷ 100). Example: an MRP of ₹11,800 at 18% gives a base price of ₹11,800 ÷ 1.18 = ₹10,000, so the GST inside it is ₹1,800. Choose “Remove GST” in this calculator and it does this for you. A common mistake is subtracting 18% of ₹11,800, which gives the wrong answer.
What are the GST rates in India?
Most goods and services fall in the standard slabs of 5%, 12%, 18% and 28%, with some items at 0% or exempt, and special rates for a few categories. Rates and exemptions are set by the GST Council and can change through official notifications, so for a real invoice confirm the current rate for your item's HSN or SAC code from official sources.
Can I use this calculator for my actual GST filing?
Use it for quick estimates, quotations and checking bills. It is not a substitute for your accountant or CA: real invoices can involve place-of-supply rules, exemptions, reverse charge, the composition scheme and input tax credit conditions that a simple calculator does not cover.