GST registration checker
Two questions to check whether GST registration is mandatory for your business — and what your deadline is if it is. Nothing you answer is stored or sent anywhere.
The rule in one paragraph
GST registration becomes compulsory when your taxable turnover crosses S$1 million — measured two ways. Looking back: if you crossed it in the calendar year that just ended, you apply by 30 January and are registered from 1 March. Looking forward: if at any point you can reasonably expect to cross it in the next 12 months, you apply within 30 days of that forecast. The expensive mistake is discovering this late — IRAS can back-date registration, and the GST you never collected comes out of your own margin.
Frequently asked questions
What counts as taxable turnover?
The value of standard-rated and zero-rated supplies your business makes — broadly, your revenue from goods and services in Singapore plus exports. It excludes exempt supplies (such as certain financial services and residential property sales) and out-of-scope transactions.
What is the difference between the retrospective and prospective basis?
Retrospective: at the end of each calendar year, you look back — if taxable turnover for that year exceeded S$1 million, registration is mandatory; apply by 30 January and you are registered from 1 March. Prospective: at any point, if you can reasonably expect to exceed S$1 million in the next 12 months (signed contracts, confirmed orders), you must apply within 30 days of that forecast.
What happens if I register late?
IRAS can back-date your registration to when you should have registered. You then account for GST on past sales even though you never collected it from customers — it comes out of your margin — and penalties can apply on top.
Is voluntary registration worth it below the threshold?
Sometimes. You can claim input GST on costs, which helps if your customers are GST-registered businesses or your inputs are GST-heavy. But you commit to charging 9% on sales, filing returns, and staying registered for at least two years. For consumer-facing businesses competing on price, that 9% can hurt more than the input claims help.
GST readiness is one signal among many. See your business’s full financial health picture — free.
Six questions, two minutes. Band-level inputs only.
Based on IRAS registration rules current as of June 2026 (source). This tool is general information, not tax advice — edge cases (exempt supplies, imported services, overseas vendors) need specific assessment.
The FHS methodology was designed by Joo Leng, CA (Singapore), FCCA — a fractional CFO. Band-level inputs only. PDPA-clean by design.