Goods and Services Tax (GST) applies to almost all sales and purchases that take place in India. Irrespective of whether one is a businessman fixing a price for his product or a buyer who wants to find out how much tax is included in the total amount he has to pay, knowledge about calculating GST becomes imperative.
What Is GST?
GST is a single indirect tax levied on the supply of goods and services, replacing the earlier system of multiple taxes like VAT, service tax, and excise duty. It is charged at different rates depending on the category of goods or services — common slabs in India are 0%, 5%, 12%, 18%, and 28%.
GST calculations come up in two common situations:
- Adding GST — you know the base price and need to find the final price including tax.
- Removing GST — you know the final price (inclusive of tax) and need to find the original base price and the tax amount separately.
GST Formulas:
To Add GST (Excluding to Including)
GST Amount = (Original Price × GST Rate) / 100
Final Price = Original Price + GST Amount
For example, a product priced at ₹1,000 has a GST rate of 18%.
GST Amount = (1000 × 18) / 100 = ₹180
Final Price = 1000 + 180 = ₹1,180
To Subtract GST (Including to Excluding)
The most common calculation mistake when it comes to calculating GST is that people assume the above logic applies. However, this formula should be used to remove GST.
Original Price = Final Price / (1 + (GST Rate / 100))
GST Amount = Final Price − Original Price
For example, the final price of a product is ₹1,180 and the product is inclusive of 18% GST.
Original Price = 1180 / (1 + 0.18) = 1180 / 1.18 = ₹1,000
GST Amount = 1180 − 1000 = ₹180
Notice how merely calculating “18% of 1180” (which equals ₹212.40) will give the incorrect answer.
CGST, SGST, and IGST
In case of transactions within the state, GST will be equally divided into CGST (Central GST) and SGST (State GST). In case of 18% GST, it will be divided into 9% CGST + 9% SGST. But in case of inter-state transactions, full GST rate will apply to IGST (Integrated GST). It does not make any difference in tax amount, just a distribution pattern of the collected tax.
Common Scenarios In Which This Becomes Important
Independent professionals or small business owners invoicing customers have to ensure the GST is properly applied on their fees without any mistake of overpaying or underpaying.
People shopping at a store can cross-check the amount of GST included in the bill with the rate applicable for that product group.
Online stores setting the price of goods need to calculate their base price by using the reverse formula to arrive at an inclusion price. The process of reconciling GST returns by accountants requires segregating the tax from the revenue.
A Quick Reference Table
| GST Rate | ₹1,000 Base Price (Inclusive) | GST Amount |
|---|---|---|
| 5% | ₹1,050 | ₹50 |
| 12% | ₹1,120 | ₹120 |
| 18% | ₹1,180 | ₹180 |
| 28% | ₹1,280 | ₹280 |
Conclusion:
While the process seems straightforward enough, GST calculations often catch people out because of the conversion from inclusive to exclusive amounts, making it easy to make mistakes. The DK Calculator GST eliminates this problem, providing you with the correct breakdown between cost and tax right away.
Content.