GST — Goods and Services Tax — is Singapore's version of a consumption tax. It sounds simple: charge it, collect it, pass it to IRAS. But the rules around when you must register, and what happens if you get it wrong, catch a lot of business owners off guard. Here's the plain-English version.
What GST actually is
GST is a tax on most goods and services sold in Singapore, currently at 9%. If your business is GST-registered, you charge it to your customers (that's your output tax), and you can claim back the GST you paid on your own business purchases (your input tax). The difference is what you pay to — or get back from — IRAS each quarter.
When you must register (the $1M rule)
Registration becomes compulsory once your taxable turnover crosses S$1 million — either looking back over the past year, or if you reasonably expect to cross it in the next 12 months.
When registering early can pay off
You can also register voluntarily below $1M — and sometimes you should. If you import a lot of goods or carry heavy GST on your purchases, registering lets you claim that input tax back instead of absorbing it as a cost. It comes with obligations (you generally stay registered at least two years and file quarterly), so it's a real decision — worth working through with someone before you commit.
The penalties that stack up
GST is one area where penalties don't come alone — they layer:
- Late registration — backdated, so you owe uncollected GST
- Late filing — a penalty that builds each quarter you're late
- Late payment — on the tax owed, growing the longer it sits
Three separate clocks, all running at once. A small slip can snowball into a serious bill — which is exactly why staying on top of it matters.
InvoiceNow: the change coming for everyone
IRAS is rolling out InvoiceNow — Singapore's national e-invoicing network — making GST-registered businesses transmit invoice data digitally. It's already required for new voluntary registrants, and phases in for everyone else by business size over the next few years. If you're still invoicing the old way, you'll need InvoiceNow-ready software before your date arrives. Better to move early than scramble at the deadline. For the full picture — including the two myths that trip people up — see our guide to InvoiceNow and the GST InvoiceNow Requirement.
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See our GST service →This article is general information, not legal or tax advice, and rules can change. ACRA, IRAS and MOM requirements are set by those authorities. For advice specific to your situation, talk to us.