Excel – Formula to calculate non-GST value from GST-inclusive amount

The following Excel formula demonstrates how to calculate the non-GST value from a GST-inclusive amount.

For example – If you have a GST-inclusive amount of $120 with a GST rate of 10%, you can use this formula to find the non-GST value.

= Amount / (1 + GST Rate)

How to use the formula

  1. In an Excel cell, enter the formula mentioned above.
  2. Replace “Amount” with the GST-inclusive value you want to calculate the non-GST value for.
  3. Replace “GST Rate” with the applicable GST rate.
  4. For example
    =120 / (1 + 0.10)
  5. Press Enter to calculate the formula.
  6. The result displayed in the cell will be the non-GST value.

The result will be the non-GST value.


  • this formula works on the principle that the GST rate is a decimal value. If you have a GST rate in percentage format, such as 10%, convert it to a decimal by dividing it by 100.