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GST Calculator

This GST calculator adds GST to a base price or removes it from a GST-inclusive total, at 5%, 12%, 18%, 28% or any custom rate, with the CGST + SGST split shown automatically. Type an amount, tap a rate, done — it all runs on your device.

  • Nothing you type leaves this page
  • Works offline once loaded
  • Free forever, no signup
Mode

GST rate

How to use this tool

  1. Enter the amount

    The base price if you are adding GST, or the GST-inclusive total (like an MRP or invoice total) if you are removing it.

  2. Choose Add or Remove GST

    Add computes tax on top of your amount; Remove extracts the base price and tax hidden inside an inclusive total.

  3. Tap a rate and read the split

    Pick 5%, 12%, 18%, 28% or type a custom rate — the base, CGST, SGST and total appear instantly, with a copy button for the full breakup.

Questions people ask

How do I remove GST from a total price?

Divide the inclusive amount by (1 + rate/100). For example, ₹1,180 at 18% → base ₹1,000 and GST ₹180 (CGST ₹90 + SGST ₹90). The Remove mode on this calculator does this instantly for any rate.

How is GST calculated on a base price?

Multiply the base by the rate: ₹1,000 at 18% adds ₹180 of GST for a total of ₹1,180. Within a state that ₹180 splits equally into ₹90 CGST and ₹90 SGST.

What is the difference between CGST, SGST and IGST?

On a sale within a state, the GST splits equally between the centre (CGST) and the state (SGST). On an interstate sale, a single IGST is charged at the full rate instead — the total tax is the same either way.

How do I calculate GST on an MRP?

MRP is always GST-inclusive, so use Remove mode: enter the MRP and the applicable rate, and the calculator shows the base price and the tax portion inside it.

Which GST rate should I pick?

Use the rate printed on your invoice or the rate notified for your goods or service — the common slabs are 5%, 12%, 18% and 28%, and the custom field accepts special rates like 0.25% or 3%. When in doubt, check the GST rate finder on the official CBIC site.

Is this GST calculator free and private?

Yes — no login, no upload. Every calculation happens in your browser and the page works offline after it loads.

Free because it costs us nothing to run: your browser does the work, not our servers. Made by Dynamb Technologies — we build software for businesses.