GST can be calculated simply by multiplying the Taxable amount by GST rate. If CGST & SGST/UTGST is to be applied then CGST and SGST both amounts are half of the total GST amount.
GST = Taxable Amount x GST Rate
If you have the amount which is already including the GST then you can calculate the GST excluding amount by below formula
GST excluding amount = GST including amount/(1+ GST rate/100)
For example: GST including amount is Rs. 525 and GST rate is 5%.
GST rates are as under
0% (necessity items like milk, wheat flour)
0.25% (rough diamonds)
3% (gold, silver etc.)
5%
12%
18%
28%
Most of the goods fall in the category of 5%, 12% and 18%, while most of the services fall in the category of 18%. GST of 28% is applicable on some items like cement, car, tobacco. There is also a Cess which is applicable only on a handful of goods like car, tobacco, pan masala.
How to make calculation of GST in case of reverse charge?
In the case of reverse charge also, the calculation will be same. For example, you have purchased goods worth Rs. 5,000 from a person and you are required to pay GST on reverse charge at the rate of 18%. So you have to pay a GST on reverse charge of Rs. 900 (5,000 x 18%). If CGST & SGST is to be levied then CGST & SGST of Rs. 450 each is to be paid.
