How to Add GST to a Price

To add GST to a price, multiply the base price by the GST rate, then add that GST amount to the base price. For example, if the base price is Rs. 10,000 and GST is 18%, GST is Rs. 1,800 and the final price is Rs. 11,800.

GST amount: GST Amount = Base Price x GST Rate / 100

Final price: Final Price = Base Price + GST Amount

Base price | GST rate | GST amount | Final price

Rs. 2,000 | 5% | Rs. 100 | Rs. 2,100

Rs. 2,000 | 12% | Rs. 240 | Rs. 2,240

Rs. 2,000 | 18% | Rs. 360 | Rs. 2,360

Rs. 2,000 | 28% | Rs. 560 | Rs. 2,560

Add GST without manual calculation: Use LinkMitra's GST Calculator to enter the base amount and GST rate, then view GST amount and final total instantly.

When this calculation is useful

Preparing a GST invoice

Creating a quotation before approval

Checking whether a selling price covers tax

Explaining tax to a customer

Comparing GST-exclusive and GST-inclusive prices

Rate reminder: Do not guess the GST rate for a product or service. Confirm the current applicable rate before billing.

Step-by-step example

Start with base price: Rs. 12,500.

Choose GST rate: 18%.

Calculate GST: 12,500 x 18 / 100 = Rs. 2,250.

Add GST to base price: 12,500 + 2,250 = Rs. 14,750.

Use Rs. 14,750 as the final GST-inclusive total.

This method works for any rate you enter. The important part is confirming that the base amount is truly GST-exclusive before adding tax.

Using the result in a quotation or invoice

After calculating GST, copy the base amount, tax amount and final amount into your quotation or invoice. If the customer is comparing prices, state whether your quoted price is plus GST or including GST. That one phrase prevents confusion when the final amount is higher than the base price.

When you create the final invoice, recheck the numbers in the GST Calculator before downloading the PDF.

How do I add 18% GST?

Multiply the base price by 18/100, then add the result to the base price.

Is GST added before or after discount?

That depends on how the transaction is structured. Check your invoice calculation rules and tax treatment before finalising.