30 November. IRAS states that the filing due date is 30 November each year. Form C-S filed through accounting software on IRAS's listing gets 15 more days, to 15 December, for YA 2023 to YA 2027. A dormant company still files by 30 November unless IRAS has granted a waiver. The return is built from the year's accounts.
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Which form does a company file?
It depends on the company. Form C-S needs annual revenue of S$5 million or below, among other conditions. Form C-S (Lite) needs annual revenue of S$200,000 or below. Every other company files Form C. Revenue is one condition for the simpler forms, and IRAS's overview sets out the rest.
Settle the form before the work starts. The form decides what the return asks for, and the accounts and tax computation have to supply it.
Who gets until 15 December?
Companies filing Form C-S through accounting software on IRAS's listing. For YA 2023 to YA 2027, IRAS automatically extends the filing due date by 15 days, from 30 November to 15 December, for Form C-S returns filed this way. The extension is stated for those Years of Assessment only.
The extension is automatic, so there is nothing to apply for. The conditions are the form, the software and the Year of Assessment.
Does a dormant company have to file?
Yes. A dormant company still files by 30 November unless IRAS has granted a waiver. Dormant is not exempt. A company that has stopped trading, and holds no waiver, works to the same due date as a company that is trading, and faces the same consequences if its return is late.
What can a late return bring?
An estimated assessment and a composition. IRAS states that a late tax return can bring an estimated assessment and a composition of up to S$5,000 per offence. Both turn on the date the return is filed. A return that is correct when it finally arrives is still a late return.
What records sit behind the return?
The year's accounts, and the records under them. The return is built from the accounts, so close the books before opening the form. IRAS requires source documents, accounting records and schedules, bank statements and other records of transactions to be kept for at least 5 years from the relevant Year of Assessment.
What order keeps the return on time?
Accounts, then tax computation, then form. Each step depends on the one before it, so a late first step makes the last one late. Book the filing for the first week of November, not the last. That leaves time for a question raised by the accounts or the computation to be answered before 30 November.
Sources
- IRAS - Overview of Form C-S, Form C-S (Lite) and Form C
Page of 11 August 2026: the annual revenue condition is S$5 million or below for Form C-S and S$200,000 or below for Form C-S (Lite).
- IRAS - Using accounting software to prepare and file Form C-S
For YA 2023 to YA 2027, IRAS automatically extends the filing due date by 15 days, from 30 November to 15 December, for Form C-S returns filed through accounting software.
- IRAS - Dormant Companies
Page of 7 August 2026: a dormant company files by 30 November unless IRAS has granted a waiver.
- IRAS - Late filing or non-filing of Corporate Income Tax Returns
Page of 10 August 2026: the filing due date is 30 November each year; a late return can bring an estimated assessment and a composition of up to S$5,000 per offence.
- IRAS - Record keeping requirements
Page of 22 January 2026: source documents, accounting records and schedules, bank statements and other records of transactions are kept for at least 5 years from the relevant Year of Assessment.