ToolSprouts
Financial CalculatorsDate & Time CalculatorsHealth CalculatorsMath CalculatorsLength ConvertersWeight ConvertersTemperature ConvertersArea ConvertersVolume ConvertersSpeed ConvertersData & File Size ConvertersDigital & Data ToolsText ToolsGenerators About Contact
Processed locally in your browser

GST Calculator

Add GST to an amount, or work out the pre-tax amount from a GST-inclusive price, at any tax rate.

Total Amount (incl. GST)
—
—
Net Amount
—
GST Amount
Estimate only: Results are for general planning purposes and do not constitute financial or investment advice. Actual amounts from your bank or lender may vary. Consult a licensed financial advisor before making financial decisions.

What Is GST?

GST (Goods and Services Tax) is a consumption tax added to the price of most goods and services. Businesses and shoppers often need to move between a tax-exclusive price (before GST) and a tax-inclusive price (after GST) — this calculator handles both directions.

Example Calculation

Adding 18% GST to a net amount of $1,000 gives a GST amount of $180 and a total of $1,180.

Removing 18% GST from a gross amount of $1,180 gives a net amount of $1,000 and GST of $180.

Formula / Calculation Method

Add GST: GST = Amount × (Rate ÷ 100); Total = Amount + GST.
Remove GST: Net = Amount ÷ (1 + Rate ÷ 100); GST = Amount − Net.

How to Use This Tool

  1. Enter the amount you want to calculate GST on.
  2. Choose the applicable GST rate.
  3. Select whether the amount excludes GST (add) or includes GST (remove).
  4. Click Calculate GST to see the breakdown.

Common Use Cases

Creating invoices with correct tax amounts
Working out the pre-tax cost of a purchase
Checking GST-inclusive receipts
Budgeting for business expenses

Related Tools

Discount CalculatorFind the sale price and amount saved after a percentage discount. Percentage CalculatorCalculate percentages, percentage change, and what percent one number is of another.

Frequently Asked Questions

Which GST rate should I use?

Use the rate that applies in your country or region for the specific goods or service — common slabs are shown in the dropdown, but always confirm the correct rate with official tax guidance.

What's the difference between 'add' and 'remove' GST?

Add GST treats your entered amount as the pre-tax (net) price and adds tax on top. Remove GST treats your entered amount as the tax-inclusive (gross) price and extracts the tax portion.