GST Calculator
Add or remove GST from any amount. Supports all Indian GST slabs.
About GST Calculator
The GST Calculator computes Goods and Services Tax for any amount, in both directions: add GST to a base price or extract the GST component from a tax-inclusive total. It supports the standard Indian slabs (5%, 12%, 18%, 28%) plus custom rates, and shows the CGST/SGST split or IGST as appropriate.
Add-GST mode starts from the taxable value, while remove-GST mode works backward from a tax-inclusive total. This distinction matters because simply subtracting the chosen percentage from an inclusive price does not recover the correct base amount.
All amounts stay in your browser — invoice figures are never uploaded. The calculator performs arithmetic only; it cannot determine the legal classification, place of supply, exemption status or input-tax-credit treatment of a transaction.
How GST Calculator works in practice
- 1Enter the base amount or the total amount.
- 2Choose whether that amount already includes GST.
- 3Pick the applicable GST rate or enter a custom one.
- 4Read the CGST/SGST (or IGST) components and the final value.
Jobs this tool is built for
- Add the applicable GST slab to a quoted pre-tax product or service price.
- Extract taxable value and tax from a GST-inclusive retail amount.
- Split intrastate tax into equal CGST and SGST components for an invoice check.
- Compare a standard slab with a custom rate while reviewing a quotation.
What you can do here
- Add-GST and remove-GST modes
- Standard Indian slab rates plus custom rates
- CGST + SGST split for intrastate, IGST for interstate
- Instant recalculation on every change
Limits and honest caveats
- Confirm the applicable GST rate and place-of-supply treatment from current official guidance or a tax professional; the calculator does not classify goods or services.
- Rounding methods used by invoicing systems can produce small differences at line-item and invoice-total level.
- The result does not account for exemptions, cess, reverse charge, input tax credit or composition-scheme rules.
Common questions about GST Calculator
What is the difference between CGST and SGST?
CGST goes to the central government and SGST to the state — both apply on intrastate transactions and together equal the total GST.
When does IGST apply?
On interstate transactions and imports — IGST equals the total GST rate and is paid to the centre.
How is GST removed from an inclusive amount?
The base is inclusive amount ÷ (1 + rate), and GST is the difference. For 18%, divide by 1.18 rather than subtracting 18% directly.
Does the calculator decide which slab applies?
No. Select the rate that applies to the specific supply after checking its current classification and tax rules.
This page was written by the ToolSink team to explain how GST Calculator works on this site — it is not syndicated, scraped, or spun from another publisher. How we write tool guides · Site updates · About ToolSink.
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