finance2026-07-163 min read

How to Remove GST from Total Amount: Formula

Learn how to remove GST from a total invoice amount using the reverse GST formula. Extract base price and tax amount in 2 simple steps.

Need to calculate the base price of a product when you only know the total price (inclusive of GST)? This is called reverse GST calculation.

The Reverse GST Formula Base Price = Total Price / (1 + GST Rate / 100)

Once you have the base price, you can find the tax amount by subtracting the base price from the total price.

Try it out on our interactive GST Calculator by selecting the "Exclusive" / "Remove GST" mode.