How to File Corporate Income Tax in Singapore: Complete Guide for YA2026

Every company incorporated or registered in Singapore must file a corporate income tax return with the Inland Revenue Authority of Singapore (IRAS) each year. This guide covers the key deadlines, forms, exemption schemes, and what your company needs to do for Year of Assessment (YA) 2026.

Singapore Corporate Tax Rate

Singapore imposes a flat corporate income tax rate of 17% on a company's chargeable income — that is, gross revenue less deductible business expenses, capital allowances, and any losses brought forward.

In practice, most Singapore-incorporated companies pay considerably less than 17%, thanks to the Start-Up Tax Exemption and Partial Tax Exemption schemes described below.

Understanding Year of Assessment (YA)

The Year of Assessment (YA) is the calendar year in which your company's income is assessed for tax. It is based on profits earned in the preceding financial year.

A company with a 31 December financial year-end earns income in FY2025 → assessed in YA2026
A company with a 31 March financial year-end earns income in the financial year ending March 2025 → also assessed in YA2026

The YA always refers to the year you file, not the year you earned the income.

Two Filing Obligations Every Company Has

Obligation 1: Estimated Chargeable Income (ECI)

ECI is your company's estimate of its taxable income for the financial year, before deducting capital allowances and losses carried forward. IRAS uses it to raise a provisional tax assessment and set up instalment payments.

Deadline: Within 3 months of your financial year-end.

For a company with a 31 December FY-end, ECI for FY2025 is due by 31 March 2026.

Filing ECI early — even before the deadline — allows IRAS to set up more monthly GIRO instalments, which helps spread your tax payment and improve cash flow.

ECI exemption: You do not need to file ECI if both of the following apply:

Annual revenue is S$5 million or less for that financial year, and
ECI is nil (zero) for that Year of Assessment

Even if exempt, companies with tax payable should still file — earlier filing means more instalments.

Obligation 2: Corporate Income Tax Return

All Singapore companies must file their annual income tax return. The form you use depends on your revenue:

Form C-S Lite — Revenue of S$200,000 or below, with straightforward income and no complex tax positions
Form C-S — Revenue of S$5 million or below
Form C — Revenue above S$5 million, or companies with complex tax positions (e.g. group relief claims, foreign tax credits, capital allowances on ships)

YA2026 filing deadline: 30 November 2026

All filings are submitted through myTax Portal using the company's UEN and CorpPass credentials. For the full list of dates and forms, see the IRAS Corporate Income Tax Filing Season 2026 page.

Important change: IRAS has unified the deadline to a single date of 30 November for all companies and all submission methods. The previous separate deadlines — 30 November for paper and 15 December for e-filing — no longer apply from YA2026 onwards.

Dormant companies and companies that had no revenue or incurred a loss must still file their income tax return by the deadline.

YA2026 Corporate Income Tax (CIT) Rebate

For YA2026, IRAS is granting a 50% CIT Rebate, capped at S$40,000.

Companies that employed at least one local employee (Singapore citizen or PR) in 2025 are also entitled to a minimum cash grant of S$2,000 — even if the 50% rebate on their actual tax liability falls below that amount.

The CIT Rebate is automatically applied to your YA2026 tax assessment
The cash grant is disbursed by IRAS directly
Do not include either in your ECI submission — they are applied after your tax is assessed

Tax Exemption Schemes

Start-Up Tax Exemption (SUTE)

Newly incorporated Singapore companies may qualify for SUTE for their first three consecutive Years of Assessment:

75% exemption on the first S$100,000 of chargeable income
50% exemption on the next S$100,000 of chargeable income

This means the effective tax rate on the first S$200,000 of chargeable income can be as low as 4.25% for qualifying startups.

To qualify, the company must:

Be incorporated in Singapore
Be a tax resident for that YA
Have no more than 20 shareholders, all of whom are individuals (or at least one individual holding a minimum 10% of ordinary shares)
Not be engaged primarily in investment holding or property development for sale

Partial Tax Exemption (PTE)

Companies that do not qualify for SUTE (including companies after their first three YAs) receive PTE on their first S$200,000 of chargeable income:

75% exemption on the first S$10,000 of chargeable income
50% exemption on the next S$190,000 of chargeable income

What Is Chargeable Income?

Chargeable income is your company's gross revenue minus allowable deductions. Getting to a clean chargeable income figure depends on well-maintained bookkeeping and accounting records. Deductible expenses typically include:

Staff costs — salaries, CPF employer contributions, staff training
Rent, utilities, and office running costs
Professional fees — accounting, legal, company secretarial
Business travel and entertainment (subject to IRAS limits)
Capital allowances on qualifying plant and machinery (in lieu of depreciation)
Losses brought forward from prior years

Non-deductible items include personal expenses charged to the company, fines and penalties, and entertainment costs that are not wholly and exclusively for business purposes.

Penalties for Late or Non-Filing

IRAS enforces compliance firmly. Consequences include:

Financial penalties of up to S$5,000 per YA for late or non-filing
Court prosecution for repeated non-compliance
Directors may be held personally responsible for the company's filing obligations — even where a tax agent has been engaged

How to File: Step by Step

Ensure your company's accounts are finalised for the financial year — profit and loss statement and balance sheet are required
Compute chargeable income with your accountant: gross income less allowable deductions, capital allowances, and prior-year losses
Log in to myTax Portal using the company's UEN and a CorpPass account with tax filing access
File ECI within 3 months of your financial year-end
Complete the appropriate Form C-S Lite / C-S / C by 30 November of the Year of Assessment

Frequently Asked Questions

Does my company need to file even if it had no revenue?

Yes. All Singapore companies — including dormant companies — must file an income tax return every year.

My company made a loss this year. Do I still need to file?

Yes. File as normal. A loss for the year can be carried forward indefinitely to offset future taxable profits, or carried back one year to claim a refund against the prior YA's tax paid.

Does my company need an audit before filing?

Most small Singapore companies qualify for audit exemption if they meet at least two of three criteria: annual revenue of S$10 million or less, total assets of S$10 million or less, or 50 or fewer employees. Audit-exempt companies still need proper accounts, but no statutory audit is required.

What if I miss the deadline?

IRAS does not routinely grant extensions. If your company faces genuine exceptional circumstances, contact IRAS before the deadline — do not wait until after it passes. Late filing penalties apply from the day after the deadline.

Can my company secretary handle this?

A company secretary handles statutory compliance (ACRA filings, AGMs, resolutions) but is not typically a licensed tax agent. Corporate income tax filing should be handled by a licensed tax agent or your company's accountant.

What about the director's personal income tax?

Directors pay personal income tax separately on their salary and director's fees.

Related Guides

Corporate tax basics

Filing mechanics

Deductions & reliefs

Related compliance

WealthBridge provides corporate tax filing services for Singapore companies at all stages — from first-year startups to growing SMEs to established corporates. Contact us for a quote.