What is a GST calculator?
A GST calculator is a free online tool that works out the tax component on any amount at a chosen GST rate.
It handles two everyday situations: adding GST to a base price to get the total amount payable, or stripping GST out of a GST-inclusive amount to find the original base price and the tax embedded in it.
The Chola Securities GST calculator covers all standard GST rate slabs — 5%, 12%, 18% and 28% — and shows the CGST and SGST split for intra-state supplies, as of 2026.
How GST is structured in India
GST replaced multiple indirect taxes with a single, destination-based tax. How it is collected depends on whether the transaction is within a state or across state lines.
| Tax type |
When it applies |
Who collects it |
| CGST |
Intra-state supply (same state) |
Central government |
| SGST |
Intra-state supply (same state) |
State government |
| IGST |
Inter-state supply or imports |
Central government |
For an intra-state transaction, the total GST is divided equally between CGST and SGST. For example, 18% GST on an intra-state sale becomes 9% CGST and 9% SGST. For an inter-state sale, the same 18% is charged as a single IGST. The total tax paid by the buyer is identical in both cases.
How does the GST calculator work?
The calculator uses two formulas depending on whether you are adding or removing GST.
Adding GST (you have the base price):
GST amount = Amount × rate%
Total inclusive amount = Amount + GST amount
Removing GST (you have the GST-inclusive total):
Base amount = Inclusive amount ÷ (1 + rate%)
GST amount = Inclusive amount − Base amount
Worked example: Take ₹10,000 as the base price at 18% GST. Adding GST gives ₹10,000 × 18% = ₹1,800, making the total inclusive amount ₹11,800 — split into CGST ₹900 and SGST ₹900 for an intra-state supply. Working in reverse from the same ₹11,800 inclusive amount, removing GST gives ₹11,800 ÷ 1.18 = ₹10,000 base, confirming that the GST embedded is ₹1,800.
Note: the calculator is for illustration and convenience only. It does not constitute tax advice. Always verify the applicable GST rate for your specific goods or service, as classifications can change. Consult a qualified tax professional for compliance matters.
How do I use Chola Securities' GST calculator?
Using the calculator takes three steps.
- Enter the amount — either the base price (to add GST) or the GST-inclusive total (to remove GST).
- Select the GST rate slab — 5%, 12%, 18% or 28%.
- Choose whether to add or remove GST.
The result updates instantly and shows the GST amount, the CGST and SGST split, and the net or gross total.
GST rate slabs in India
Most goods and services fall into one of four main GST slabs, with some items at 0% or fully exempt.
| Slab |
What it typically covers |
| 0% / Exempt |
Essential food items, certain healthcare and education services |
| 5% |
Common-use goods and services, packaged food, economy transport |
| 12% |
A range of processed goods and services |
| 18% |
Most widely applied slab, covering a large share of goods and most services |
| 28% |
Luxury and select non-essential goods |
Registered businesses can claim input tax credit (ITC) — the GST paid on business purchases can be set off against the GST collected on sales, so tax is effectively paid only on the value added. As of 2026, always confirm the exact rate and ITC eligibility for your specific goods or services.
Why use the GST calculator?
- Work out the exact tax amount and total payable before raising an invoice or quote.
- Check what portion of a GST-inclusive price is the actual base cost.
- See the CGST and SGST split for intra-state transactions without manual calculation.
- Avoid arithmetic errors when dealing with different rate slabs across multiple line items.