GST Calculator

Add GST to a price, or take GST out of a GST-inclusive amount, at Singapore's 9% or any rate you set. Paste several amounts to do a whole list at once. Free, no signup, nothing leaves your browser.

Full guide: How to make an invoice, including Singapore tax invoices →

Typing GST into invoices by hand?

Accounting software and a simple automation can create GST-correct invoices from your orders, so nobody retypes amounts or rates.

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How to add GST

GST = price before GST × rate ÷ 100. At 9%, S$1,000 before GST carries S$90 of GST, so the price including GST is S$1,090.

How to remove GST from a GST-inclusive price

GST included = GST-inclusive amount × rate ÷ (100 + rate). At 9% that is 9/109 of the total. S$1,000 including GST contains S$1,000 × 9 ÷ 109 = S$82.57 of GST, so the price before GST is S$917.43. Dividing by 1.09 gives the same answer.

A common mistake is taking 9% off the GST-inclusive price: 9% of S$1,000 is S$90, which overstates the GST by S$7.43.

GST in Singapore, briefly

The standard rate has been 9% since 1 January 2024.
Only GST-registered businesses may charge GST, and they must show it correctly on tax invoices.
Prices shown to the public by GST-registered businesses generally have to include GST.
Check IRAS for the rules that apply to your business; this calculator does the arithmetic, not tax advice.

Need the invoice too? The free invoice generator adds GST and switches to a tax invoice automatically.

Questions

How do I calculate 9% GST? Multiply the price before GST by 0.09 for the GST, or by 1.09 for the price including GST. S$500 becomes S$545 including S$45 of GST.

How do I remove GST from a total? Multiply the GST-inclusive total by 9/109 to get the GST included, or divide it by 1.09 to get the price before GST.

Can I use another rate? Yes. Change the GST rate box to any rate, for example for another country's VAT or GST.

More free calculators: break-even, gross profit, price increase, DSO, GST, invoice due date and all free tools.

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