Tips on e-Filing Form C-S

Getting your Access Code and authorising an "Approver" for "Corporate Tax Matters" beforehand, and other useful tips on e-Filing Form C-S.

Before e-Filing Form C-S

Before you use the "File Form C-S/ C" e-Service to complete and file Form C-S, please do the following:

  1. Confirm that the company meets the qualifying conditions for filing Form C-S.
  2. Ensure that you have been duly authorised by the company as an "Approver" for "Corporate Tax Matters" via the e-Services Authorisation System (EASY).
  3. Ensure that you have the company's tax reference number and your personal SingPass or IRAS PIN.
  4. Get ready the company's financial accounts and tax computation. You may wish to use the Basic Corporate Tax Calculator to prepare your tax computation.

Set aside at least 10 minutes to complete this electronic tax return.

You do not need to submit the company's financial statements, tax computation and supporting documents/ schedules together with Form C-S. However, you need to prepare them and submit them to IRAS upon its request. For more details on submission of claim forms, please refer to Documents to Prepare when Filing Form C-S/ C.

e-File Form C-S in 4 Simple Steps

Step 1: Retrieve your company's existing e-Services Access Code

  1. Request a new Access Code by downloading the application form if:
    • Your company does not have an Access Code; or
    • Its existing Access Code is no longer valid.
  2. Complete and submit the form to IRAS via fax or email.

You may skip this step if you already know your company's Access Code.

Step 2: Authorise Yourself/ Third Party as an "Approver"

You need to authorise yourself/ third party as an "Approver" for "Corporate Tax Matters" before you or the third party can e-File.

  1. Log in to the e-Services Authorisation System (EASY) using your company's Access Code.
  2. Authorise yourself/ third party as an "Approver" for "Corporate Tax Matters" and log out.

You may skip this step if you have already authorised an "Approver".

Step 3: Log in to myTax Portal

  1. Log in to
  2. Select Organisation/ Business Tax Matters and choose either SingPass or IRAS PIN login.
  3. Key in your personal SingPass or IRAS PIN, followed by your Organisation Tax Ref No.

Step 4: Submit the Completed Form C-S Online

  1. Click on Corporate Tax and select File Form C-S/ C at the main menu of Please note that there is no Form C-S (Upload) service. e-Filing of Form C-S can only be done via the online Form C-S.
  2. Select the Year of Assessment (YA) you are filing and select Form C-S to begin completing the Form.
  3. Click on Confirmation Page after you have completed the Form. Please save/ print the Confirmation Page before clicking on Submit.
  4. You will receive an instant acknowledgement upon successful filing.

Points to Note when e-Filing

Filing Deadline

Your company enjoys the extended filing due date of 15 Dec , instead of 30 Nov when you e-File Form C-S.

Online Help

For guidance on how to complete Form C-S, please:

  • Click on the iHelp icon <i2 >; or
  • Click on " Ask IRAS" at the top of the page.

Save Draft Facility

If you are not able to complete your filing in one session, please save the Form C-S as 'draft'. The draft will be retained in the portal up to 15 Dec. You can access the draft anytime till 15 Dec and make the necessary amendments before you submit your Form C-S.


Please do not leave your filing session idle for more than 20 minutes. Otherwise, the session will expire and you will be required to log in to the portal again. If you are unable to complete your filing in one sitting, do remember to save a draft of your filing before you log out from

New Companies Filing First Tax Return

If your company's first set of financial accounts covers a period of more than 12 months from its date of incorporation, please indicate "Yes" in the "For Newly Incorporated Companies filing its first Tax Return" section of Part A.

In completing Part B of Form C-S, you will need to:

  1. Attribute the company's adjusted profit/ losses before other deductions to two YAs* (i.e. YA 2016 and YA 2017). This is because, in general, the basis period for each YA should not exceed 12 months; and
  2. Complete the line items for two YAs in the e-Form C-S.

* Time apportionment basis may be used if the company is unable to directly identify the adjusted profit/ losses before other deductions to the corresponding basis period for each YA.

Company A was incorporated in Singapore on 15 Jul 2015. The financial year end of the company is 31 Dec. Company A's first set of accounts was prepared for the period from 15 Jul 2015 to 31 Dec 2016.

As the first set of accounts covered a period of more than 12 months, the two relevant YAs are as follows:

YABasis Period
2016 (1st YA)15 Jul 2015 - 31 Dec 2015
2017 (2nd YA)1 Jan 2016 - 31 Dec 2016

In this case, Company A has to attribute its adjusted profit/ losses before other deductions to YA 2016 and YA 2017 respectively via the direct identification method.

Where the company is not able to apply the direct identification method, the time apportionment basis may be used (i.e. apportion company's income on time basis to the period from 15 Jul 2015 to 31 Dec 2015 [YA 2016] and the period from 1 Jan 2016 to 31 Dec 2016 [YA 2017]).

Once the adjusted profit/ losses before other deductions has been attributed to YA 2016 and YA 2017, Company A will need to complete the line items for YA 2016 and YA 2017 in the e-Form C-S accordingly.

For more information on YA and basis period for new companies, please refer to Overview of Corporate Income Tax.

Acknowledgement of Successful e-Filing

Upon successful e-Filing, you will receive an instant acknowledgement. The same acknowledgement page will also be available at under the "View Corporate Tax Notices" e-Service.

Details on Completing Form C-S Online

User Guides

Detailed User Guides for:

Frequently Asked Questions (FAQs)

For more details on e-Filing of Form C-S, please refer to our FAQs (364KB).

Contact Us

Please contact us if you need assistance or clarification on Form C-S e-Filing:

  • Email us via myTax Mail
  • IRAS Helpline: 1800-356 8622 (8 a.m. to 5 p.m. from Mon to Fri)


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