About the GST Calculator
This GST calculator adds GST to a base price or removes it from a GST-inclusive price in one step. Enter an amount, pick the rate and choose the direction, and it shows the GST amount, the total or the base value, and the equal split between CGST and SGST — or the same tax as IGST for an inter-state supply.
It is handy for shopkeepers, traders, freelancers, accountants and anyone preparing a quotation, checking a supplier's bill or working backwards from an MRP. Because the reverse calculation is built in, you do not have to remember the formula for extracting tax from an inclusive price, which is where most manual errors happen.
Only two things drive the result: the amount and the rate. The tool offers 0.25%, 3%, 5%, 12%, 18% and 28%. The correct rate depends on the HSN or SAC code of what you sell, and GST rates are revised from time to time on the GST Council's recommendation, so confirm the rate currently notified for your item before you invoice.
How to use it
- 1Enter the amount in rupees.
- 2Select the GST rate that applies to your goods or service.
- 3Choose “Add GST” if the amount is before tax, or “Remove GST” if the amount already includes tax.
- 4Read the total or base amount, the GST amount and the CGST and SGST split; for an inter-state sale, treat the full GST amount as IGST.
How this is calculated
Add GST: GST = amount × rate ÷ 100; total = amount + GST. Remove GST: base = inclusive amount ÷ (1 + rate ÷ 100); GST = inclusive amount − base. Within a state, CGST = SGST = GST ÷ 2. For an inter-state supply, IGST = GST.
Frequently asked questions
How do I add GST to a price?
Multiply the base price by the GST rate and add the result. For ₹10,000 at 18%, GST is ₹1,800 and the invoice total is ₹11,800. In this GST calculator, choose “Add GST”, enter 10000 and select 18% to get the same figures, together with the CGST and SGST break-up of ₹900 each.
How do I remove GST from a GST-inclusive amount?
Divide the inclusive amount by 1 plus the rate. For ₹11,800 at 18%, the base is ₹11,800 ÷ 1.18 = ₹10,000 and the GST is ₹1,800. Select “Remove GST” to use the tool as a reverse GST calculator. Simply deducting 18% from ₹11,800 would give ₹2,124, which overstates the tax.
How is GST split between CGST, SGST and IGST?
For a supply within the same state, the tax is shared equally: half is CGST for the Centre and half is SGST for the state. For a supply from one state to another, the whole amount is charged as IGST. The calculator shows the CGST and SGST split and notes the equivalent IGST figure.
Which rates does this GST calculator support?
The rate list offers 0.25%, 3%, 5%, 12%, 18% and 28%. A custom rate cannot be typed in, and cess is not calculated. GST slabs and item-wise rates are revised by the government on the GST Council's recommendation, so check the rate currently notified for your HSN or SAC code on the official GST or CBIC portal.
Is GST charged on the price before or after a discount?
GST is generally charged on the transaction value, so a discount shown on the invoice at the time of supply reduces the taxable amount. Enter the price after such a discount as the base amount. Discounts given later are governed by specific conditions in the GST law, so consult your accountant for those cases.
Can I use the result directly on my invoice?
Use it as a quick reference. The tool does not check whether the rate you chose is right for your item, and it does not handle compensation cess, the composition scheme or reverse charge. For a ready document, the free GST invoice generator on this site applies the same arithmetic line by line.