CORPORATE TAX GUIDE · SINGAPORE
Corporate tax filing deadline: 30 November 2026
Most of the work behind a corporate tax return happens well before the deadline. This guide sets out which year you are actually filing for, what the return needs behind it, and a sensible order of work between now and 30 November.
THE SHORT ANSWER
Form C-S, Form C-S (Lite) or Form C for YA 2026 is due by 30 November 2026.
YA 2026 covers the financial year that ended during 2025 — not the year you are trading through now. The deadline is the same 30 November whatever month your financial year ends in.
Source: IRAS guidance on the Corporate Income Tax return. Confirm the position for your company before filing.
FIRST, THE PART PEOPLE GET WRONG
Which year are you filing for?
A Year of Assessment is the year the income is assessed, and it runs one year behind the financial year that produced it. This trips up more first-time filers than any other part of the process. If your financial year ended at any point during 2025, you are filing for YA 2026 by 30 November 2026.
| Financial year end | Year of Assessment | Return due |
|---|---|---|
| 31 December 2025The most common financial year end for Singapore SMEs. | YA 2026 | 30 November 2026 |
| 30 June 2025A mid-year FYE does not move the return deadline. | YA 2026 | 30 November 2026 |
| 31 March 2025Same deadline again — only the ECI date differs. | YA 2026 | 30 November 2026 |
| 31 December 2026A financial year ending in 2026 is next year's filing. | YA 2027 | 30 November 2027 |
WHAT THE DEADLINE ACTUALLY REQUIRES
The form is the last step, not the work.
Filing on time means having three things finished, in this order. A simplified return does not remove any of them.
Financial statements
A closed set of accounts for the financial year, with the bank and control accounts reconciled and year-end adjustments posted.
A tax computation
The statement that adjusts accounting profit to chargeable income, with schedules supporting every adjustment and claim.
The right return
Form C-S, Form C-S (Lite) or Form C, depending on the conditions the company meets for the Year of Assessment.
A SENSIBLE ORDER OF WORK
Working backwards from 30 November.
These are planning guides rather than rules — a company with clean monthly books can compress them considerably, and one with a year of unreconciled records will need longer. The point is that the last fortnight is for review, not for finding invoices.
Now to end August
Close the financial year properly
Finish the bookkeeping, reconcile the bank and control accounts, chase missing invoices and post year-end adjustments. Everything downstream depends on a set of accounts that will not move again.
September
Prepare the tax computation
Adjust accounting profit for non-deductible items, capital allowances, non-taxable income and any brought-forward amounts. This is the work that takes the longest when records are incomplete.
Early October
Confirm which return applies
Check the conditions for Form C-S, Form C-S (Lite) or Form C before drafting. Discovering the company does not qualify for the simplified return in late November is an avoidable problem.
Mid to late October
Draft and review the return
Complete the return, tie every figure back to the computation and the accounts, and leave time for a second read. Questions surface at this stage, not earlier.
Early November
File with room to spare
Filing a few weeks early leaves space for a missing document, a director who is travelling or a question that needs an answer. The deadline falls on a Monday, so the weekend before it is not working time you can rely on.
IF YOU HAVE NOT STARTED
Start with the year, not the form.
- 01
Confirm the financial year you are filing for, and therefore the Year of Assessment. Everything else follows from this.
- 02
Get the books to a closeable state before worrying about the form. A return cannot be prepared from incomplete records.
- 03
Pull last year's tax computation and Notice of Assessment — brought-forward items and prior positions start there.
- 04
Identify anything unusual this year: asset purchases or disposals, related-party transactions, foreign income, a change of shareholding.
- 05
Ask for help early rather than late. The work is the same in October and in the last week of November, but the room to fix problems is not.
THREE DEADLINES THAT GET MIXED UP
30 November is one of three, and they are not the same filing.
Two go to IRAS and one goes to ACRA. Meeting one does not satisfy another, and only the corporate income tax return is fixed to a calendar date.
ECI
Within three months after FYE
An early estimate of taxable profit, filed shortly after the financial year closes. A company may qualify for a waiver when annual revenue is S$5 million or below and ECI is nil.
Read the ECI guideACRA Annual Return
Within seven months after FYE
A separate filing with ACRA, not IRAS. It follows the AGM, which non-listed companies generally hold within six months after the financial year end.
Calculate the Annual Return dateCorporate income tax return
30 November
Form C-S, Form C-S (Lite) or Form C, declaring the company's actual income for the Year of Assessment. This is the deadline this guide covers.
Compare the return formsIF THE DATE PASSES
A missed return does not stay quiet.
Where a return is not filed, IRAS may raise an estimated assessment based on the information available to it. That assessment is payable even while it is being disputed, and correcting it afterwards takes more work than filing would have. If the deadline has already passed, file as soon as the return can be properly supported rather than waiting until the records are perfect.
Read IRAS guidance on late or non-filingCommon questions.
What is the corporate tax filing deadline in Singapore?
The annual corporate income tax return — Form C-S, Form C-S (Lite) or Form C — is due by 30 November each year. For YA 2026 that means 30 November 2026, covering the financial year that ended in 2025.
Which financial year does the 30 November 2026 deadline cover?
YA 2026 assesses income from the financial year that ended during 2025. A company with a 31 December 2025 financial year end and a company with a 30 June 2025 financial year end both file for YA 2026 by 30 November 2026.
Is the deadline different if my financial year end is not December?
No. The annual return deadline is 30 November regardless of the financial year end month. What changes is the ECI date, which is generally within three months after the financial year end, and the ACRA Annual Return date, which follows the financial year end separately.
Do I still need to file if the company made a loss or was dormant?
Companies generally report their income to IRAS each year, including dormant companies, unless IRAS has granted a waiver from filing. A loss-making year does not remove the filing obligation, and unutilised losses need to be recorded properly if you want to carry them forward.
What do I need to have ready before filing?
The financial statements for the year, a tax computation with supporting schedules, and the records behind them — the general ledger, bank reconciliations, fixed-asset register and prior-year tax computation. Companies filing Form C-S or Form C-S (Lite) prepare the computation and retain it; Form C filers submit the required documents with the return.
What happens if the return is filed late?
Late filing can lead to enforcement action from IRAS, and IRAS may raise an estimated assessment based on the information it holds. An estimated assessment still has to be paid even if the company disputes it, so filing on time is considerably easier than correcting it afterwards. Check the current IRAS guidance for the consequences that apply to your situation.
This guide provides general information, not tax or legal advice. Filing requirements depend on a company's circumstances and records, and IRAS guidance is updated from time to time. Confirm your company's position before filing.