GST calculator for Singapore: add or remove 9% GST

What is 9% GST on common amounts?

To add 9% GST, multiply by 1.09. To find the GST inside a GST-inclusive price, multiply by 9/109 (about 0.0826). To get back to the price before GST, divide by 1.09. Every figure below is rounded to the nearest cent.

What is the GST rate in Singapore?

Singapore's standard GST rate is 9%, in force since 1 January 2024. It was 8% during 2023 and 7% from 1 July 2007 to the end of 2022, according to IRAS's current and historical GST rates. GST began on 1 April 1994 at 3%.

Not every sale carries 9%. IRAS sorts supplies into four kinds: standard-rated (9%, most local sales), zero-rated (0%, such as exported goods and international services), exempt (such as the sale and rental of unfurnished residential property, and financial services) and out-of-scope (such as goods shipped from one overseas place to another).

Which rate applies when a sale straddles a rate change?

The time of supply is normally the earlier of the invoice date and the payment date (IRAS time of supply rules), so use that date in the calculator's date picker. When the invoice, payment and delivery fall on different sides of a change, IRAS's transitional rules apply. For the 2024 change, if you invoiced in 2023 and were fully paid or fully delivered in 2023, the whole sale stays at 8%; otherwise 9% applies to the lower of the payment received and the value delivered from 1 January 2024. An invoice dated from 1 January 2024 for goods delivered or payment received in 2023 could take 8% on the higher of those 2023 amounts.

How do you calculate GST in Singapore?

Multiply the price before GST by 9% to get the GST, and add it to the price; or multiply by 1.09 for the GST-inclusive price in one step. On S$250 that is S$22.50 of GST and S$272.50 in total.

With several items, IRAS accepts two methods: work out 9% on each line and add the results, or apply 9% once to the subtotal. They can differ by a cent. IRAS's own example is three pens at S$1.28: per line, the GST is S$0.12 three times, S$0.36; on the subtotal of S$3.84 it is S$0.35. Either is acceptable if you use one consistently. Tick Several items above, enter 1.28 three times and switch between On the total and Per line to see both.

Round the total GST to the nearest cent. You may also round the whole bill to the nearest 5 cents for cash payments; rounding up or down is your decision, but it must be the same every time.

How do you remove GST from a price?

Multiply the GST-inclusive price by 9/109 to find the GST in it, then subtract that from the price; or divide the price by 1.09. A S$109 price contains S$9.00 of GST and S$100.00 before GST.

The common error is taking 9% of the GST-inclusive price: on S$109 that gives S$9.81, which is 81 cents too much. IRAS uses the fraction in its own example of a bargained price: an item displayed at S$109 sells for S$90, so the GST to account for is 9/109 × S$90 = S$7.43 (IRAS price display guidance). For a 2023 price use 8/108, and 7/107 for earlier years.

Who must register for GST in Singapore?

A business must register when its taxable turnover exceeds S$1 million, judged in two ways (IRAS: Do I need to register for GST):

• Retrospective: taxable turnover for the calendar year was more than S$1 million. Apply between 1 and 30 January; registration takes effect on 1 March.
• Prospective: you can reasonably expect more than S$1 million in the next 12 months, backed by evidence such as signed contracts. Apply within 30 days of that forecast; for forecasts from 1 July 2025, registration takes effect two months after the forecast date.

Taxable turnover counts standard-rated and zero-rated sales, not exempt or out-of-scope sales or capital assets. Register late and IRAS backdates the registration: you owe GST on past sales you never collected it on, and may face a fine of up to S$10,000 plus a penalty of 10% of the GST due.

Below the threshold you can register voluntarily, but you must stay registered for at least two years, and a business that applies to register voluntarily on or after 1 April 2026 must also send invoice data to IRAS through InvoiceNow (IRAS GST InvoiceNow Requirement). A business that is not registered may not charge GST at all.

How must GST-registered businesses display prices?

Inclusive of GST, wherever the public sees a price: tags, price lists, adverts, websites and quotes, written or spoken. Not complying can bring a fine of up to S$5,000 (IRAS).

A registered business that gives a discount equal to the GST must not advertise it as "no GST": the GST is still in the price and still owed to IRAS.

Is GST charged on service charge in Singapore?

Yes. IRAS treats service charge as part of the price, so GST is charged on the food and drinks plus the service charge (IRAS: Hotel and Food & Beverage). A S$100 meal with 10% service charge is S$110 before GST, S$9.90 of GST and S$119.90 in total, which is what the F&B bill mode shows. At 10% and 9% the quick multiplier is 1.199.

Hotels and F&B outlets that impose a service charge may show prices before GST and service charge, with a prominent statement such as "Prices are subject to GST and service charge". Takeaway-only items without a service charge must still be shown GST-inclusive.

Common mistakes when calculating GST

• Taking 9% of a GST-inclusive price instead of 9/109 of it.
• Leaving the service charge out of the amount GST is charged on.
• Applying 9% to a sale whose time of supply fell in 2023, or 8% to one in 2024.
• Rounding GST per line on some invoices and on the subtotal on others.
• Charging GST before your registration takes effect, or without being registered.
• Charging 9% on zero-rated or exempt sales. Collecting GST where none is chargeable, without reasonable excuse or through negligence, is an offence (IRAS).

How Olano helps

Olano Studio builds AI agents for Singapore businesses' admin and customer work. An operations agent can triage the shared inbox, draft replies from your own price lists and run recurring admin on a schedule, with anything outbound waiting for your approval (AI inbox assistant). If your books are in QuickBooks Online, an agent can also draft invoices and record payments in the connected company (Olano user guide), set to ask a person before it writes anything. It does not replace your accountant or IRAS's guidance. Every engagement is quoted as a fixed proposal in Singapore dollars, exclusive of GST; see our services or discuss a project.