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Reverse GST Calculator: extract GST from any price

Know the final price but need the base value and tax inside it? The Reverse GST Calculator does it instantly. Here's how.

By the Launch My Office team · Updated 2026-06-22 · 5 min read

Sometimes you have a GST-inclusive price (an MRP) and need to work backwards to the base amount and the GST inside it. Doing this by hand is error-prone; the Reverse GST Calculator gets it right every time.

The formula behind it

To remove GST from an inclusive price: base = inclusive ÷ (1 + rate). The GST amount is the difference. For example, ₹1,180 at 18% gives a base of ₹1,000 and GST of ₹180.

Inclusive priceRateBaseGST
₹1,0505%₹1,000₹50
₹1,12012%₹1,000₹120
₹1,18018%₹1,000₹180
₹1,28028%₹1,000₹280

When sellers need this

Use it in three steps

  1. Open the Reverse GST Calculator.
  2. Enter the GST-inclusive amount.
  3. Pick the GST rate (find it with the HSN Code Finder) and read the base and tax.
Pair this with the inclusive vs exclusive pricing guide to decide how to display prices to customers.

Need this done for you?

Our in-house CA & CS team set up your virtual office, VPOB and GST end to end — from ₹15,290/yr.

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Frequently asked questions

How do I remove GST from a price?

Divide the inclusive price by (1 + rate). For 18%, divide by 1.18 to get the base; the remainder is GST. The calculator does this automatically.

Is the Reverse GST Calculator free?

Yes, it's free and instant, with no sign-up required.

Which rate should I choose?

The rate for your product, determined by its HSN code. Use the free HSN Code Finder if you're unsure.

Talk to an expert

Get a free callback

Leave your details and our in-house CA & CS team will call you back — usually within a few business hours. No spam, no obligation.

  • ✓ Free consultation on VPOB, APOB & GST
  • ✓ Transparent pricing from ₹15,290/yr
  • ✓ Same-day document pack on most plans

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