Corporate Income Tax Filing Season 2021

This page provides you with information on Corporate Income Tax filing to help you better understand companies' tax filing obligations.

The deadline for filing your Corporate Income Tax Return (Form C-S/ C) for the Year of Assessment (YA) 2021 is 30 Nov 2021. This deadline of 30 Nov will similarly apply to subsequent YAs.

Electronic filing of Form C-S/ C is compulsory for all companies.

The File Form C-S/ C e-Service for YA 2021 is available at now.

Key Tax Changes for YA 2021

To continue providing support for companies:
- Companies are given the option to claim the Renovation & Refurbishment (R&R) deduction in one YA (i.e. accelerated R&R deduction) instead of over three YAs for qualifying R&R expenditure incurred during the basis period for YA 2021.

- Companies are given an option to accelerate the write-off of plant and machinery (P&M) over two years, instead of three years or over the prescribed working life of the asset, on the cost incurred in acquiring such P&M during the basis period for YA 2021.  

- Companies may elect for either the current carry-back relief system or enhanced carry-back relief system for YA 2021.

Form C-S (Lite)

This is a simplified version of Form C-S. Learn more about Form C-S (Lite) here.

You can file Form C-S (Lite) if your company qualifies to file Form C-S and has an annual revenue of $200,000 or below.   

Filing of the Corporate Income Tax Return

How do I file via

In order to file via, you have to first be authorised by the company to act for its Corporate Income Tax matters via Corppass. View our step-by-step guides for assistance on Corppass setup.  

Which Corporate Income Tax Return do I file (Form C-S, Form C-S (Lite) or Form C)?

Form C-S is for companies which fulfil all of the below conditions:

  • Are incorporated in Singapore
  • Have an annual revenue of $5 million or less
  • Derive income taxable at the prevailing corporate tax rate of 17%
  • Not claiming the following:
    1. Carry-back of Current Year Capital Allowances/ Losses
    2. Group Relief
    3. Investment Allowance
    4. Foreign Tax Credit and Tax Deducted at Source

You can file Form C-S (Lite) if your company qualifies to file Form C-S and has an annual revenue of $200,000 or below.

Form C is for companies which do not qualify to file Form C-S. Financial statements, tax computations and supporting schedules must be filed together with Form C.

Do I need to file my Corporate Income Tax Return for YA 2021? 

- Company was newly incorporated in 2020

- Company was in a loss position for the financial year ending 2020

- Company was dormant for the financial year ending 2020

- Company's YA 2020 tax assessment is currently under IRAS’ review

Company was newly incorporated in 2020

Yes, if your company closed its first set of financial statements in 2020, and derived income or started business in 2020.

Visit our Basic Guide for New Companies page where you can get help with filing your company’s tax returns for the first time. You can also access the New Company Start-Up Kit, an interactive guide to learn more about Corporate Income Tax filing obligations. It customises your filing information, provides useful tips and generates email reminders about your tax filing obligations. 

Year of Incorporation Year the first set of Accounts is ClosedDo I need to file for YA 2021?What needs to be done 
2019 2020 Yes
 2020 2020Yes, if your company commenced business or received income in 2020
  • File your YA 2021 tax return
 2020 2021 No
  • No action required
 2021 2021 No
  • No action required


Company was in a loss position for the financial year ending 2020

Yes, you have to file your Corporate Income Tax Return as long as you have carried out business.

Company was dormant for the financial year ending 2020

Yes, you have to file your Corporate Income Tax Return, unless your company has been granted a waiver to file the return. 

If your company did not carry on business and had no income for the whole financial year ending 2020, it will be regarded as a dormant company for YA 2021. You may file your Corporate Income Tax Return using the “File Form C-S/ C for Dormant Company” e-Service at

More details can be found at Dormant Companies

Company's YA 2020 tax assessment is currently under IRAS' review

Yes, you have to file the YA 2021 Corporate Income Tax Return based on the YA 2020 tax position filed with IRAS. The same deadline of 30 Nov 2021 applies. 

Any unutilised loss items and tax written down values of assets (for the purposes of computing capital allowances) to be carried forward to YA 2021, for setoff against the taxable income of YA 2021, should be based on the YA 2020 tax computation prepared by your company.  

When filing, the brought forward unutilised amounts in the current YA fields will be pre-filled with the carried forward amounts declared by the company in the YA 2020 Form C-S/ C.

Learn more about the Corporate Income Tax Return review process at: Tax Assessment Process.

Preparing a Tax Computation

What income is taxable?

Taxable income refers to:

  1. gains or profits from any trade or business;
  2. income from investment such as dividends, interest and rental;
  3. royalties, premiums and any other profits from property; and
  4. other gains that is revenue in nature.

Income is taxable when it is:

  1. accrued in or derived from Singapore; or
  2. received in Singapore from outside Singapore

Learn more about taxable and non-taxable income or watch this video on the Taxability of Income (5m 44s).

What expenses are deductible and what are the common tax reliefs and deductions for companies?

You may claim tax deductions on expenses 'wholly and exclusively' incurred in the production of income.

Learn more about deductions for different types of expenses and the tax reliefs available to lower your tax burden. You may also watch this video on the Tax Deductibility of Expenses (4m 59s).

Common filing mistakes to avoid

  • Wrongful claims of non-deductible expenses:
    1. Interest expenses attributable to non-income producing assets or investments that produce exempt dividends
    2. S-plated cars purchased for business use, including the cost of the car and the associated running expenses
  • Understatement of income e.g. omission of particular receipts or invoices issued or transactions settled in cash
  • Failure to keep proper records and accounts, resulting in the understatement of sales or overstatement of expenses in tax returns

View common Corporate Income Tax Return filing mistakes at Specific Compliance-Related Mistakes and Issues.

Working out my company's tax payable

Use the IRAS Basic Tax Calculator to compute the amount of taxes your company has to pay. Explanatory notes to guide you through tax computation and validation checks against common errors are included in the calculator.

Preparing tax computation of an investment holding company?

An investment holding company is a company that owns investments such as properties and shares for long term investment, and derives investment income (non-trade income) such as dividend, interest or rental income. 

Learn how to prepare the tax computation for investment holding companies.

Filing Status

Checking the status of my Corporate Income Tax Return submission and assessment

The status of your company's Corporate Income Tax Return and tax assessment can be found at or through the Corporate Tax Integrated Phone Service. Learn more about how to check your Form C-S/ C submission and assessment status.

Your company’s filing status may only be viewed at the “View Corporate Tax Filing Status” e-Service at three working days after you have filed your company’s Form C-S/ C.

Making changes to my Corporate Income Tax Return submission

Revise the amount declared and/ or submit a revised tax computation via the “Revise/ Object to Assessment” e-Service at Learn more about making changes to your company’s tax submission.

Tax Bill

When will I get my tax bill?

View the IRAS Tax Assessment Process for an overview of the tax return review cycle and timeline that you can expect to get your tax bill, also known as the Notice of Assessment (NOA). After your NOA is issued, you can also access it via the "View Corporate Tax Notices (PDF, 198KB)" e-Service at

Disputing my tax bill

File your objection via the “Revise/ Object to Assessment” e-Service at within two months from the date of the NOA if you wish to have your tax assessment reviewed and revised. 

Learn more about the Objection and Appeal process

Paying my tax

Payment must be made within one month from the date of the NOA, notwithstanding any objections. Payment modes include GIRO (preferred), PayNow QR, AXS, Internet Banking and other electronic payment modes. Learn more about payment methods for Corporate Income Tax.

Refund for my tax credit

Tax credits are automatically refunded within 30 days from the date the credit arose. There is no need to submit a claim.

If your company pays taxes through GIRO from its own bank account, it will receive the refund to the same bank account. For all other payment methods, you will receive a cheque that is valid only for three months from the date of issuance. 

Learn more about tax refunds.

Tax Assistance

Refer to the relevant guides for assistance to file your Corporate Income Tax Return: 
Form C-S Form C 

User Guide - Form C-S/ Form C-S (Lite) (Company) (PDF, 1.35MB)

Tips on e-Filing Form C-S

FAQs - Form C-S/ Form C-S (Lite) (PDF, 379KB)

User Guide - Form C (Company) (PDF, 1.96MB)

Tips on e-Filing Form C

FAQs - Form C (PDF, 411KB)


We encourage you to file early. Penalties and enforcement actions may be taken for late or non-filing of your company’s Corporate Income Tax Return.  

For Form C-S filers, you can also use the Digital Solution created by the IRAS and the Accounting and Corporate Regulatory Authority (ACRA). This solution allows companies to automate the preparation and filing of Form C-S and Annual Return to IRAS and ACRA respectively via accounting software. The digital solution leverages the Application Programming Interface (API) to simplify the tax filing process for companies and reduces their risk of making errors. Learn more about the digital solution.

You can also access our e-Learning videos to learn more about Corporate Tax.