GST Calculator
Add or remove GST from an amount, with the correct CGST+SGST or IGST split.
- Free — no signup, no account, no watermark
- Runs entirely in your browser — nothing is uploaded to a server
- Works on mobile, tablet and desktop
- Instant — results appear as soon as you enter your input
Why this is private
- Calculated locally in your browser. Nothing you enter is uploaded or stored.
- Open your browser's DevTools → Network tab while using this tool — you won't see a request carrying your input, because it never leaves your device.
- Nothing you enter is uploaded to a server or shared with us — the processing happens entirely on your device.
Overview
Calculates GST (Goods and Services Tax) either by adding it to a net amount or extracting it from a gross, tax-inclusive amount, and splits it correctly into CGST + SGST for an intra-state transaction or a single IGST line for an inter-state one.
How to use it
- 1Enter the amount.
- 2Choose the GST rate (5%, 12%, 18%, 28% or a custom rate).
- 3Toggle between "Add GST" and "Remove GST".
- 4Choose Intra-state or Inter-state to get the correct CGST+SGST or IGST split.
- 5View the tax breakdown and final price.
Formula
Add GST
Final = Amount × (1 + rate/100)
Remove GST
Base = Amount / (1 + rate/100)
Intra-state split
CGST = SGST = GST amount ÷ 2
Inter-state split
IGST = full GST amount
Examples
Add 18% GST to ₹1,000, intra-state
GST = ₹180 total → CGST ₹90 + SGST ₹90, final price = ₹1,180.
Add 18% GST to ₹1,000, inter-state
IGST = ₹180 (single line), final price = ₹1,180 — the total is identical to the intra-state case, only the invoice split differs.
Remove 18% GST from ₹1,180
Base price = ₹1,000, GST component = ₹180.
Frequently asked questions
What people use it for
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GST Calculator