IRAS Singapore: How It Works and What You Need (2025)

How to stay compliant with IRAS?

IRAS in Singapore believes most taxpayers are willing to comply, they just need support. Here’s how you can stay on track:

For Individuals

Even if you’re not a business owner, you may still need to deal with IRAS every year. Here’s what to check:

• File your tax return if required – You must file if your total income is more than $22,000 or your self-employed net income is more than $6,000 in the past year.
• Check pre-filled info carefully – Being on the Auto-Inclusion Scheme means your details might be pre-filled. But it’s worth checking, just in case you’ve changed jobs, earned rental income, or used CPF to buy a home.
• Declare all side income – Tuition, freelance gigs, Grab driving, influencer deals, and online sales – all count as income and must be declared.
• Respond to IRAS notices – Think there’s an error in your tax bill or need to change your info? Just inform IRAS within 30 days.

For Businesses and Self-employed Individuals

Running a business in Singapore means staying on top of multiple filing and reporting requirements. Here’s what IRAS expects:

• File your Estimated Chargeable Income (ECI) – This must be done within 3 months after your financial year ends, unless you qualify for a waiver.

• Submit your annual tax return – Choose the correct form (Form C, C-S, or C-S Lite) based on your company size and revenue.
• Register for GST – If your taxable turnover crosses S$1 million in a 12-month period, GST registration is mandatory. You can also register voluntarily if it benefits your business.
• Keep proper records for 5 years – This means keeping things like receipts, invoices, bank statements, and tax papers. Small businesses might be able to use Simplified Record-Keeping.
• Don’t claim private or inflated expenses – Personal groceries, home utilities, or family trips shouldn’t be included as business expenses.
• Disclose any mistake – Use IRAS’s Voluntary Disclosure Programme to correct past errors. If you come forward early, you may get reduced or waived penalties.

Common IRAS compliance red flags in Singapore

IRAS doesn’t aim to penalise, but it does monitor these red flags to ensure fair compliance:

1. Under-reported income

This is especially common in cash-heavy and online businesses such as retail shops, influencers, tutors, and online sellers.

2. Withholding tax

Payments made to overseas vendors for services may be subject to withholding tax, even if you’re a startup or new business.

3. Incorrect GST claims

Some businesses, especially dormant or home-based ones, mistakenly claim GST on private expenses or on purchases without valid tax invoices.

4. Using shell companies to reduce tax

Setting up multiple companies just to split income or reduce tax exposure may trigger audit scrutiny.

5. Big-ticket asset purchases that don’t match your declared income

If you buy a high-value property or luxury car without a corresponding income trail, IRAS may follow up to ensure everything adds up.

6. Low-value GST refund claims and missing documentation

Dormant or home-based businesses may be audited if they make frequent small GST refund claims without supporting tax invoices, permits, or export records.