GST Calculator
Calculate goods and services tax in either direction. Add GST to a net price, or strip it out of a total to find the original price and the tax it contains.
- Runs in your browser
- No sign-up
- Free to use
How to use GST Calculator
- Enter the amount.
- Choose whether that amount excludes GST (add tax) or already includes it (remove tax).
- Pick a GST rate from the buttons or type a custom rate.
- Read the net price, GST amount and gross total, with the CGST and SGST or IGST split.
GST Calculator features
Add or remove GST
Works forwards from a net price and backwards from a tax-inclusive total.
Common rate buttons
One tap for 5%, 12%, 18%, 28% and 40%, plus a field for any other rate.
CGST, SGST and IGST split
Shows the tax divided equally for sales within a state, or as a single IGST figure for sales between states.
Works for any VAT or sales tax
Enter your country's rate to use it as a general tax calculator.
Formula shown
See the exact calculation behind the result.
Copy-ready figures
Amounts are formatted in your chosen currency.
When to use GST Calculator
- Preparing an invoice and needing the tax amount on a net price.
- Finding the pre-tax price of something quoted inclusive of GST.
- Checking the tax on a supplier's bill.
- Comparing prices quoted with and without tax.
GST Calculator FAQ
How do I add GST to a price?
Multiply the price by the GST rate and add the result. For a price of 1,000 at 18%: GST = 1,000 × 18 ÷ 100 = 180, so the total is 1,180.
How do I remove GST from an inclusive price?
Divide the inclusive price by (1 + rate ÷ 100). For 1,180 at 18%: 1,180 ÷ 1.18 = 1,000 net, so the GST is 180. Simply taking 18% off the inclusive price gives the wrong answer.
What are CGST, SGST and IGST?
In India, a sale within one state is taxed half as Central GST and half as State GST. A sale between states is charged a single Integrated GST at the full rate. The total tax is the same either way.
What GST rates apply in India?
For years most goods and services fell into slabs of 5%, 12%, 18% and 28%. A restructuring announced by the GST Council in September 2025 moved most items to 5% or 18%, with a higher 40% rate for certain luxury and sin goods. Rates are revised from time to time, so confirm the current rate for your product or service.
Can I use this for VAT or sales tax in other countries?
Yes. The arithmetic is the same for any percentage tax. Enter your rate in the custom field, for example 20 for UK VAT or 10 for Australian GST.
Exclusive and inclusive prices
A tax-exclusive price is the amount before tax; an inclusive price already contains it. Going from exclusive to inclusive is straightforward multiplication. Going the other way catches many people out, because the tax is a percentage of the net price, not of the total. An 18% tax makes up 18 ÷ 118, about 15.25%, of the inclusive amount.
GST is a value-added tax: it is charged at each stage of the supply chain, and registered businesses reclaim the tax they have paid on their purchases. Only the final consumer bears the full amount. That is why invoices show the taxable value and the tax separately, and why getting the split right matters for anyone issuing or checking a bill.