GST Calculator (Singapore)

Singapore raised GST in two steps: from 7% to 8% on 1 January 2023, then to 9% on 1 January 2024, where it stands today. The staged rise left a long tail of stale content — calculators and guides still hardcoding 8%, or even 7% — and a 1-point error compounds fast on invoices: on a S$10,000 contract it is S$100 of tax mis-stated. This page carries a verification date and the current rate, checked against IRAS and the standard professional summaries.

GST applies to most goods and services supplied in Singapore and to imports. Two categories sit outside the standard charge and are easy to confuse: zero-rated supplies — exports of goods and international services — are taxed at 0% but still count as taxable supplies, while exempt supplies — most financial services, the sale and rental of residential property, digital payment tokens, and investment precious metals — sit outside the GST net entirely. The distinction matters for businesses because zero-rated sales preserve the right to claim input tax on purchases; exempt sales generally do not.

For everyday arithmetic the rule is one line: multiply by 1.09 to add GST, divide by 1.09 to remove it. The calculator's GST tab does both directions at whatever rate you set — 9% by default.

A GST-inclusive price is not stripped of GST by taking 9% off it. The inclusive price is the net plus 9% of the net, so the GST inside it is a smaller share than 9% of the total. From a S$109.00 receipt, the correct arithmetic is S$109.00 ÷ 1.09 = S$100.00 net, with S$9.00 of GST. Subtracting 9% of the gross instead gives S$99.19 — S$0.81 wrong on a small receipt, and eighty dollars wrong on a S$10,900 invoice.

The check is the round trip: a correct net, multiplied back by 1.09, reconstructs the receipt exactly. The wrong method never survives that test. The same division logic applies at any rate, which is why the rate field is editable: the calculator handles historical 8% documents from 2023, or a comparison against a neighbouring country's rate, with the same arithmetic.

GST registration is compulsory once taxable supplies exceed S$1 million over a 12-month period — a deliberately high threshold that keeps most freelancers and small traders outside the system. Below it, registration is voluntary: worthwhile mainly for businesses selling to GST-registered customers (who reclaim the tax anyway) or carrying heavy input costs, and it comes with the full compliance duty once taken. If you are unregistered, you charge no GST and this calculator's markup and margin tabs apply to your prices directly.

One consumer-facing rule is worth knowing whichever side of the counter you are on: prices displayed to the public in Singapore must be GST-inclusive — the price on the shelf or menu is the price you pay. The common exception people notice is food and beverage establishments showing the "++" convention (service charge plus GST added at the bill); for most other retail, an ex-GST display to consumers is not permitted. For business-to-business quotes, ex-GST pricing is normal — which is exactly the workflow the calculator's tabs cover: set a net price with the markup or margin tab, then add 9% for the inclusive figure.

The markup and margin tabs answer the pricing question that comes before tax, and the two percentages are not interchangeable. Markup measures profit against cost: price = cost × (1 + markup). Margin measures the same profit against the selling price: price = cost ÷ (1 − margin). A S$700 cost at 30% markup sells for S$910; at a 30% margin it must sell for S$1,000. Work both on net, GST-exclusive figures — for a registered business the 9% collected on top is output tax owed to IRAS, net of the input tax on your own purchases, and computing a margin against the inclusive price flatters it artificially.

What this page deliberately does not do: file anything, handle import GST reliefs, or model scheme-specific arrangements (the Major Exporter Scheme, reverse charge on imported services for partially exempt businesses, and similar are specialist territory). It computes the arithmetic every GST situation shares — inclusive, exclusive, and the tax in between — with the current rate as the default, and IRAS remains the authority where a specific supply's treatment is in question.