How do I add GST to a price in Singapore?

Multiply the price before GST by 9% and add the result. IRAS’s current GST rates page gives the rate as 9% for GST-registered businesses on sales of goods and services in Singapore, unless the sale can be zero-rated or exempted. A S$2,400 job comes to S$2,400 + S$216 GST = S$2,616.00 (our illustration). The tool above does the same sum and rounds to the nearest cent.

How do I take the GST out of a price that already includes it?

Multiply the GST-inclusive price by 9/109, which IRAS calls the tax fraction. IRAS’s page on displaying and quoting prices uses it for a retail price that is bargained down: a product priced at $109 sells for $90, and the GST to account for is 9/109 × $90 = $7.43. On a price of S$1,090 the GST inside it is S$90.00 and the price before GST is S$1,000.00 (our illustration, not IRAS’s).

Does it matter how GST is worked out on an invoice with several lines?

It can, by a cent. IRAS’s invoicing page allows two methods on a tax invoice with several items: apply 9% to each item and add up the GST, or apply 9% once to the sum of the items. It says the total can differ because of rounding, that both methods are acceptable and that you must apply the one you choose consistently. IRAS’s own example is three pens at $1.28 each before GST: by item that is $0.12 × 3 = $0.36 of GST and $4.20 in all, and on the $3.84 sum it is $0.35 and $4.19. The tool’s third mode starts with that example and shows both. For a line with a quantity above 1 it takes 9% of the line total (quantity × price), which is our reading, since IRAS’s example has one of each.

How does the tool round?

IRAS says you can round the total GST to the nearest cent, and that you may round the total bill to the nearest 5 cents if you choose. It does not say which way half a cent goes, so the tool rounds half a cent up (our convention) and does not round bills to 5 cents. Use the setting in your accounting software and keep it consistent.

What does this calculator not do?

It does not decide whether a sale is standard-rated, zero-rated or exempt. IRAS’s overview of GST lists exports of goods and international services as zero-rated, and the sale and rental of unfurnished residential property and financial services as exempt. It does not check whether you must be registered, and its results are working figures, not a format for a public price quote. Our guide to how GST appears on quotes, invoices and credit notes has worked examples, and the guide to when to register for GST covers the S$1 million threshold.

What is the GST rate in Singapore in 2026?

9%, according to IRAS’s current GST rates page, read on 3 October 2026 (the page says “Last updated 13 June 2025”). Only GST-registered businesses charge it.

How do I work out the GST in a price that includes GST?

Multiply the price by 9/109. IRAS’s example on its price-quoting page: 9/109 × $90 = $7.43.

Can a business that is not registered for GST charge it?

No, says IRAS’s overview: non-registered businesses are not allowed to charge or claim GST. It names one exception: a non-registered person, such as a mortgagee, financier or auctioneer, that sells or rents out a registered business’s assets in satisfaction of a debt owed.

Can a GST-registered business quote a price plus GST?

IRAS says it must display and quote prices inclusive of GST to the public, including written or verbal quotes, and lists “$100 + GST” as an unacceptable format, with an exception for hotels and food and beverage establishments that impose a service charge. We found nothing on that page about a quote to a single GST-registered business, so ask IRAS about those.

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