The calculation of IGV or General Sales Tax is made by applying 18% in case of having the base amount, for example:
IGV = Base Amount x 0.18
In case of knowing the total amount, that is, including VAT, then the calculation would be as follows:
First we get the base amount as follows:
Base Amount = Total Amount / (1 + 0.18) or Base Amount = Total Amount / 1.18
Finally, subtracting the total amount minus the base amount gives us the IGV:
IGV = Total Amount – Base Amount
The result shows both options. One in case of knowing the Base Amount, the other in case of having the Total Amount and you want to know what the Base Amount is.
Base Amount + IGV = Total Amount
