Understanding corporate tax in Singapore is essential for every business owner here. Singapore’s corporate tax system is one of the most competitive in Asia – but the obligations are real and the deadlines matter. This guide to corporate tax Singapore covers rates, exemptions, GST, filing requirements, and the mistakes that attract IRAS attention.
Corporate tax Singapore: rates and exemptions
Singapore companies pay corporate income tax on chargeable income at a headline rate of 17%. In practice, most SMEs pay significantly less due to generous exemptions.
Partial tax exemption (permanent, all companies): Every Singapore company gets a partial tax exemption on the first S$200,000 of chargeable income – 75% on the first S$10,000 and 50% on the next S$190,000.
Start-up tax exemption (first three years): Newly incorporated qualifying companies get a more generous exemption – 75% on the first S$100,000 and 50% on the next S$100,000. The company must be incorporated in Singapore, be tax resident here, and have no more than 20 shareholders with at least one individual holding at least 10% of shares. In practice, a qualifying new company can earn up to S$200,000 in chargeable income and pay an effective rate of around 4.25%.
What you must file with IRAS
Estimated Chargeable Income (ECI): Due within 3 months of your financial year end. All companies must file unless specifically waived (revenue ≤ S$5M and nil chargeable income – both conditions must be met). Don’t assume you’re waived without checking. Missing ECI means IRAS issues an estimated assessment that may be higher than your actual income.
Form C-S or Form C: The annual corporate tax return, due 30 November each year. Most Singapore SMEs qualify for the simplified Form C-S if annual revenue is S$5 million or less and certain conditions are met. Filing is done through IRAS myTax Portal.
Allowable deductions
Expenses are deductible if incurred wholly and exclusively in the production of income. Deductible items include staff costs (salaries, CPF), rent, professional fees, business travel, marketing, capital allowances on fixed assets, and interest on business loans. Private expenses, capital items, and expenses related to non-taxable income are not deductible. Singapore’s Accelerated Capital Allowance scheme lets qualifying fixed assets be written off over one or three years.
GST: when you need to register
GST is currently levied at 9%. Mandatory GST registration applies when taxable turnover in the past 12 months exceeds S$1 million, or when you reasonably expect it to in the next 12 months. Registration must be done within 30 days of becoming liable – late registration means IRAS can back-assess GST from the date you became liable.
Voluntary registration makes sense when most clients are GST-registered businesses. They can claim back the GST you charge, so it doesn’t reduce your competitiveness – while you benefit from claiming input tax on your own expenses. From 1 April 2026, new voluntary GST registrations require InvoiceNow (PEPPOL e-invoicing) compliance. GST-registered businesses file Form F5 quarterly, within one month of each accounting period end.
Withholding tax on overseas payments
Singapore companies paying certain amounts to non-residents must withhold a portion and remit it to IRAS. Affected payments include interest (15%), royalties and licence fees (10%), technical service fees (17%), management fees to overseas related parties (17%), and director fees to non-resident directors (22%). Singapore has DTAs with over 90 countries that can reduce these rates. Withholding tax must be remitted within one month of payment – late remittance attracts a 5% penalty plus 1% per month thereafter.
Key Singapore tax deadlines
| Obligation | Deadline |
|---|---|
| ECI filing | Within 3 months of financial year end |
| Form C-S / Form C | 30 November each year |
| GST return (Form F5) | Within 1 month after each quarterly period end |
| Withholding tax | Within 1 month of payment date |
Common mistakes that attract IRAS attention
The most frequent issues: claiming non-deductible expenses (private costs, entertainment above limits, capital items as revenue), wrong revenue recognition periods, failing to withhold on overseas payments, late GST registration after crossing the S$1 million threshold, and incorrect input tax claims. IRAS takes a particularly close look at transactions with related overseas entities.
Need help with corporate tax Singapore filing?
Tax compliance is one area where the cost of getting it wrong – penalties, back taxes, interest – typically exceeds the cost of professional help. Abacus handles corporate income tax and GST filing for Singapore companies, including ECI, Form C-S, withholding tax management, and GST registration. Contact us to discuss your tax compliance needs.
