Almost every operator who opens their first Singapore outlet makes the same mistake in the same order. They print a menu with clean round numbers. They add the service charge everyone else adds. Then a guest points at the bill and asks why an eighteen-dollar plate cost 21.56, and there is no good answer at the table — because the answer is a tax rule, and it should have been settled before the menu went to the printer.
Here is the rule, and the trade it forces on you.
First, the arithmetic, because the order matters
“$18++” is Singapore shorthand. The first plus is service charge, conventionally 10%. The second is GST, which has been 9% since 1 January 2024. They are not added side by side — GST is charged on the total consideration, and the service charge is part of that consideration, so it goes on first and GST is calculated on the larger figure.
Eighteen becomes 19.80, and 19.80 becomes 21.58. Not 21.42, which is what you get if you naively add 19%. The compounding is 19.9%, and a till that gets the sequence wrong under-collects GST on every single ticket.
Worth being clear on one thing: no Singapore law requires a 10% service charge. It is industry custom, not statute. You can charge it, change it, or not charge it. What you cannot do is charge it quietly.
Second, the rule you would expect
The Inland Revenue Authority of Singapore (IRAS) requires GST-registered businesses to display GST-inclusive prices. Any price shown to the public — menu, poster, website, or a figure quoted verbally over the phone — is supposed to be the amount the customer will actually pay. Failing to comply is an offence, with a fine of up to $5,000.
By that rule, your eighteen-dollar plate should be advertised at 21.58.
Third, the exception you are almost certainly relying on
IRAS grants an exception to hotels and F&B establishments that impose a service charge: they may display GST-exclusive prices. The stated reason is operational. A venue that serves the same dish dine-in and takeaway, with service charge on dine-in only, would otherwise have to run two price lists or recompute every price when the charge is waived.
The exception comes with conditions, and they are the part people skip.
You must display a prominent statement telling customers that displayed prices are subject to GST and service charge. Not a footnote in six-point grey at the bottom of page four — prominent. If you run a QR menu as well as a printed one, the notice has to be on the QR menu too; that is a display to the public like any other.
The service charge has to be genuine. IRAS has said it will not extend the exception to establishments that levy a nominal service charge with no real business reason beyond avoiding inclusive display, and in 2022 it acted against restaurants charging as little as 0.1% to do exactly that.
And if you do not impose a service charge at all, there is no exception. Every displayed price must be GST-inclusive. This is the one that catches casual and fast-casual concepts, who decide service charge does not suit their positioning and then keep pricing exclusive out of habit.
Fourth, it is being argued about right now
Do not treat the exception as permanent furniture. On 26 February 2026 in Parliament, MP Kenneth Tiong argued during the MOF debate that the concession lets venues advertise prices roughly 17% below what customers pay, dismissed the dine-in-versus-takeaway justification as arithmetically neutral, and asked IRAS to run a public feedback exercise on whether the concession still serves the public interest.
Separately, the Competition and Consumer Commission of Singapore (CCCS) administers the Consumer Protection (Fair Trading) Act, and its Guidelines on Price Transparency — in force since 1 November 2020 — already treat drip pricing as a potential unfair practice where unavoidable fees are kept out of the headline price. We could find no enacted amendment banning drip pricing outright, and as of today the IRAS exception stands. But the direction of travel is one way, and the practical read is this: if you design your menu so it only works when the guest is surprised at the end, you have built on ground that is moving.
What this means for setting up the till
Service charge has to be a configurable line on the bill, not something baked into item prices, because you will waive it for takeaway. GST has to compute on the post-service-charge subtotal. Both lines have to print separately on the receipt, and the displayed menu price needs to be a distinct field from the charged price so the printed menu, the QR menu and the till never drift apart.
That much is ordinary configuration and works in any market. What we will not do is tell you whether your particular service charge qualifies for the IRAS exception, or sign off on your menu wording — that is a question for a Singapore tax adviser, and a confident wrong answer there costs real money. Tell us where the shop is and we will confirm what the system genuinely supports in that country before you buy.
Checked against the sources named above on 2026-09-20. Rules and platform terms change — confirm anything tax-related with a local accountant before you rely on it.
