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Reverse GST Calculator

This reverse GST calculator is set to Remove mode by default, because that's the direction most people searching for it actually need — extracting the base price and tax hidden inside an MRP or an invoice total. Type the inclusive amount, pick a rate, and the base price, GST and CGST/SGST split appear instantly.

  • 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 GST-inclusive amount

    This is the MRP, invoice total, or any price that already has GST added — not the base price.

  2. Pick the applicable GST rate

    Tap 5%, 12%, 18%, 28%, or type a custom rate for special cases.

  3. Read the extracted base price and tax split

    The base price, GST amount and the CGST/SGST breakup appear instantly, with a copy button for the full breakup.

Questions people ask

How do I remove GST from a total amount?

Divide the inclusive amount by (1 + rate/100). For an ₹1,180 total at 18% GST: ₹1,180 ÷ 1.18 = ₹1,000 base price, so the GST portion is ₹180 (CGST ₹90 + SGST ₹90). This calculator does that division for you the instant you type an amount.

How do I do a reverse calculation of GST from an MRP?

MRP is always GST-inclusive by law, so use this Remove mode directly: type the MRP, select the rate printed on the product or invoice, and the base price and tax portion inside it appear immediately.

What is the formula to extract base price from GST-inclusive amount?

Base price = Inclusive amount ÷ (1 + GST rate/100). It is not the same as subtracting the rate percentage directly from the inclusive amount — that common mistake overstates the base price.

How is the CGST and SGST split calculated in reverse mode?

Once the base price and total GST are extracted, the tax splits equally into CGST and SGST for an intra-state supply — for example ₹180 total GST becomes ₹90 CGST + ₹90 SGST. Interstate supplies instead charge a single IGST at the full rate.

Can I still add GST on this page instead of removing it?

Yes — tap the Add GST toggle to switch direction; this page simply opens on Remove because that's the more common intent for a 'reverse GST calculator' search.

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.