Accounting Solutions Singapore Editorial Team · Last reviewed 18 October 2026
Most small businesses don’t need to charge GST. Once your taxable sales pass S$1 million, you do, and the clock for applying is short. Some businesses below that level register anyway because it helps them. This page covers both routes, what the application involves and what changes afterwards. We prepare and submit the application for you either way.
At a glance
| Question | Short answer |
|---|---|
| GST rate | 9% on most goods and services |
| When must you register? | When your taxable turnover goes above S$1 million, or you reasonably expect it to in the next 12 months |
| How long do you have to apply? | 30 days from the point you become liable |
| Can you register earlier? | Yes, voluntarily, if you meet IRAS’s conditions. You generally stay registered for at least two years |
| Where do you apply? | IRAS myTax Portal |
| After registering | Charge GST, file GST F5 returns, and keep tax invoices. New voluntary registrants must also meet the InvoiceNow requirement |
Do you have to register?
There are two tests. Either one makes registration compulsory.
- The past-turnover test. Your taxable turnover for the calendar year went above S$1 million. Apply within 30 days of the end of that year.
- The forward-looking test. You have reasonable grounds to expect your taxable turnover in the next 12 months to go above S$1 million. Apply within 30 days of the date you form that expectation.
“Taxable turnover” counts your standard-rated and zero-rated supplies, including exports. Exempt supplies and out-of-scope transactions are treated differently. If you’re not sure how a revenue stream is classified, ask before you count.
Example (illustration only). ABC Pte Ltd has taxable turnover of S$1.2 million for calendar year 2026. It must apply by 30 January 2027. Separately, if ABC signs a large contract on 14 March 2027 that it expects to take its next 12 months’ taxable sales above S$1 million, the forward-looking test is met on that day and it must apply within 30 days, by 13 April 2027.
The forward-looking test is the one people miss, because nothing in your accounts flags it. A signed contract, a new customer or a new product line can trigger it between year ends. Once you’re getting close to the threshold, review your forecast every month, not only at year end.
What happens if you don’t register on time
IRAS’s GST guide says that failing to register when required is an offence. On conviction the fine can be up to S$10,000. There can also be a penalty of 10% of the tax due for each year or part of a year, counted from the date you should have registered, and a further S$50 for each day the offence continues after conviction. That’s why we’d rather you check early.
Voluntary registration
You can register below the S$1 million level. It’s worth considering when most of your customers are GST-registered businesses, because registering lets you claim input tax on your own business purchases. Think it through first, though:
- You must charge GST on taxable sales and file returns, usually quarterly, whether or not you’re better off.
- Minimum period. Voluntary registrants generally have to stay registered for at least two years.
- InvoiceNow. If you apply for voluntary registration on or after 1 April 2026, you need to issue invoices through InvoiceNow-ready software from the effective date of registration. Read our InvoiceNow page.
- Training. IRAS requires a director or the person preparing your GST returns to complete its “Overview of GST” e-learning course and quiz before the application is submitted, unless a waiver applies.
- If your customers are mostly consumers, registering usually adds a cost to your prices without a matching benefit.
If most of your sales are zero-rated or you only make a few taxable supplies, you may also be able to apply for exemption from registration. See our page on GST registration exemption.
What the application involves
- Confirm that you need to register, and which route. We check your turnover and forecast.
- Prepare the details IRAS asks for. Your UEN, business activities, expected turnover and financial year end, plus records supporting the turnover figure. IRAS may ask for more, such as financial statements, contracts or invoices.
- Submit through the myTax Portal, with the right person authorised through Corppass.
- IRAS assesses it. Voluntary applications can take longer, as IRAS checks that the conditions are met.
- You receive a GST registration number. It goes on every tax invoice you issue from then on.
What changes once you’re registered
- You charge 9% GST on taxable supplies, and you need a valid tax invoice for each.
- You file a GST F5 return, usually every quarter, and pay what you owe after deducting the GST on your own business purchases. Our GST compliance and filing page covers the returns.
- You can claim input tax if you meet IRAS’s conditions. See conditions for claiming GST input tax.
- Your prices, contracts and bookkeeping need to handle GST from the effective date of registration.
If you registered recently, you may also be able to claim GST on some goods you held, and on certain services you bought, in the six months before you registered. The conditions are in IRAS’s guidance.
Who this is for
- Businesses close to S$1 million in taxable sales, or expecting a big step up
- Businesses that sell mostly to GST-registered customers and want to claim input tax
- New companies that want to know before they invoice
- Businesses that think they should have registered earlier and want to check
Questions we get asked
Is my turnover S$1 million including exempt sales? No. The test counts taxable supplies, meaning standard-rated and zero-rated ones.
I’m a new company with no sales yet. Do I register? Not unless you reasonably expect your taxable turnover over the next 12 months to go above S$1 million. Voluntary registration is a separate choice.
Can I cancel my registration if it doesn’t suit me? Voluntary registrants generally need to stay registered for at least two years, so decide carefully first.
We think we passed S$1 million some time ago. Tell us as soon as you can. The sooner it’s reviewed, the easier it is to correct. We’ll tell you what the position is and what IRAS expects.
Check whether you need to register
Send us your last 12 months of sales and what you expect for the year ahead. We’ll tell you whether you must register, whether it makes sense to do so voluntarily, and what the application would involve. Check whether you need to register. For the wider picture, see our GST services overview.
Sources
- IRAS, Do I need to register for GST and Applying for GST registration
- IRAS, GST: General Guide for Businesses (section 61 penalties; paragraphs 5.2 and 6.2)
- IRAS, GST InvoiceNow Requirement e-Tax Guide (2nd edition, 9 March 2026)
This page is general information as at the date above, not legal, regulatory or professional advice. Rules change, so please take advice on your own circumstances before acting.