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GST Calculator

Calculator

Calculate GST on any amount — add or remove 10% GST instantly. Perfect for invoicing, BAS preparation, and pricing decisions.

Free to useNo data storedAI insightsUpdated: February 2026

GST (Goods and Services Tax) is a 10% tax on most goods, services, and other items sold or consumed in Australia. Whether you're preparing an invoice, checking a supplier's pricing, or lodging your BAS, getting the GST calculation right is essential. This calculator handles all three scenarios: adding GST to a net amount, removing GST from a gross amount, and extracting just the GST component.

Enter Your Details

Enter Your Details

$

The amount you want to calculate GST on

Choose whether to add, remove, or extract GST

GST registration is compulsory if turnover exceeds $75,000

Not all goods and services attract GST

Real-World Examples

Adding GST to a Quote

A web designer quotes $5,000 for a project (GST-exclusive).

GST: $5,000 × 10% = $500. GST-inclusive total: $5,500. The invoice should show: Subtotal $5,000 + GST $500 = Total $5,500.

Finding GST in a Receipt

A business owner buys office supplies for $330 (GST-inclusive) and needs to know the GST for their BAS.

GST component: $330 ÷ 11 = $30. GST-exclusive amount: $300. The $30 is claimable as an input tax credit on the next BAS.

Frequently Asked Questions

Glossary

GST
Goods and Services Tax — a 10% broad-based consumption tax on most goods, services, and other items sold or consumed in Australia.
Input Tax Credit
The GST included in the price of business purchases. GST-registered businesses can claim these credits on their BAS, effectively recovering the GST paid on business expenses.
Tax Invoice
A document issued by a GST-registered supplier showing the price, GST amount, supplier's ABN, and other required details. Required for purchases over $82.50 to claim input credits.
BAS (Business Activity Statement)
A form submitted to the ATO (quarterly or monthly) reporting GST collected, GST paid, PAYG withholding, and PAYG instalments.

Disclaimer: This calculator provides estimates only and should not be relied upon for financial decisions. Interest rates, fees, and policies change frequently. Always verify information with lenders directly. This is general information, not personal financial advice. Consider seeking advice from a licensed mortgage broker or financial advisor.

Last updated: February 2026

How to Use
  1. Enter the dollar amount.
  2. Choose your calculation type: add GST, remove GST, or find GST only.
  3. Indicate your GST registration status.
  4. Optionally select the supply type (some items are GST-free).
  5. Get instant results with a breakdown.
Key Information
  • GST is 10% of the GST-exclusive price. To find GST in a GST-inclusive price, divide by 11.
  • GST registration is mandatory if your annual turnover is $75,000+ (or $150,000+ for non-profits).
  • GST-free items include most basic food, medical services, education, and exports.
  • Input-taxed supplies (financial services, residential rent) don't include GST, and you can't claim input credits.
Pro Tips
  • Quick mental math: to add GST, multiply by 1.1. To remove GST, divide by 1.1. To find GST only, divide by 11.
  • Always show GST separately on tax invoices for amounts over $82.50 — your customers need it to claim input credits.
  • Register for GST voluntarily even under $75,000 if your customers are businesses — they prefer suppliers who are GST-registered.
  • Lodge your BAS monthly if you get regular GST refunds (more expenses than income) to improve cash flow.
Avoid These Mistakes
  • Calculating GST as 10% of the GST-inclusive price — this is wrong. GST on $110 inclusive is $10 (÷11), not $11 (×10%).
  • Charging GST when you're not registered — you cannot charge GST unless you have a valid ABN and GST registration.
  • Forgetting to claim input tax credits on business purchases — every GST-inclusive purchase is a tax credit waiting to be claimed.
  • Not issuing proper tax invoices — without a valid tax invoice, your customers can't claim the GST credit.
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