GST (goods and services tax) is added to the price of most goods and services in India. Two questions come up again and again: what is the final price with GST, and how much GST is hidden inside a price that already includes it? The GST calculator answers both.
GST rates for different items change from time to time, so check the current rate for your product or service before you use a figure.
Adding GST to a price
Multiply the price by the rate to get the GST, then add it.
GST = price x rate / 100
Final price = price + GST
Example: a price of Rs 1,000 with GST at 18%.
- GST: 1,000 x 18% = Rs 180.
- Final price: 1,000 + 180 = Rs 1,180.
Removing GST from a price
When a price already includes GST, you cannot just subtract 18% of it. The tax was worked out on the lower base price, not on the final price.
Base price = final price / (1 + rate / 100)
Example: a final price of Rs 1,180 with GST at 18%.
- Base price: 1,180 / 1.18 = Rs 1,000.
- GST inside the price: 1,180 - 1,000 = Rs 180.
The common mistake is to take 18% of Rs 1,180, which gives Rs 212.40 and a wrong base price of Rs 967.60.
CGST, SGST and IGST
The tax is split depending on where the sale happens.
- Within one state: the tax is shared equally between the Centre (CGST) and the state (SGST). At 18% that is 9% each, so Rs 90 and Rs 90 on a Rs 1,000 base price.
- Between states: the full tax is charged as IGST. At 18% on Rs 1,000, that is Rs 180.
The total tax is the same. Only the label on the invoice changes. The calculator has an option for both cases.
Who needs this
- Shoppers checking how much of a bill is tax.
- Small sellers preparing a bill. A tool like the GST invoice generator can build the full invoice.
- Anyone comparing two quotes where one includes GST and the other does not.
Steps
- Open the GST calculator.
- Enter the amount and the GST rate.
- Choose add GST or remove GST.
- Pick the within-state or between-state split.
- Read the base price, the GST and the final price.
This is an estimate for understanding a bill. For filing returns, follow the official rules and speak to an accountant.