Tips on e-Filing Form C-S

Singapore Corporate Access (or Corppass) is the sole authorisation system for entities to manage digital service access of employees who need to perform corporate transactions with government agencies online. To access IRAS digital services, you must first be authorised via Corppass. Follow the Step-by-Step Guides on how to register for Corppass.

From 11 Apr 2021, you will be required to log in to government digital services for businesses (G2B) using Singpass instead of Corppass. For more information, visit Corppass website.

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. If your company has an annual revenue of $200,000 or below, you can choose to file Form C-S (Lite), a simplified version of Form C-S, from YA 2020.
  2. Ensure that you have been duly authorised by the company as an "Approver" for "Corporate Tax (Filing and Applications)" in Corppass.
  3. Ensure that you have your Singpass as well as the company's Unique Entity Number (UEN)/ Entity ID.
  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 3 Simple Steps

Step 1: Ensure that you or the third party has been authorised as an "Approver"

The company will need to authorise you/ the third party as an "Approver" for "Corporate Tax (Filing and Applications)" in Corppass before you or the third party can e-File. For assistance on Corppass setup, please refer to the relevant Step-by-Step Guides

Step 2: Log in to myTax Portal

  1. Log in to
  2. (i) If you are logging in as a staff of the company, select "Business Tax" and log in with your Singpass.  

      (ii) If you are logging in as a tax agent of the company, select "Tax Agent Login" and log in with your Singpass.  

    Step 3: Submit the Completed Form C-S Online

    1. Click on Corporate Tax and select File Form C-S/ C at the main menu of
    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.

    For more detailed guides on e-Filing Form C-S:
    - Guidance on Completing Form C-S

      Points to Note when e-Filing

      Filing Deadline

      From YA 2021, the annual filing deadline for Form C-S is 30 Nov.

      Online Help

      Please click on the iHelp icon  <iHelp icon > should you require on-the-spot guidance as you e-File the Form C-S.

      Particulars of Person who Reviewed the Return New!

      With effect from YA 2021, a new field has been included in Form C-S (including Form C-S (Lite)) and Form C for a company to indicate if its return has been reviewed by a person who is a Singapore Chartered Tax Professionals Limited (SCTP) Accredited Tax Advisor or Accredited Tax Practitioner for Income Tax. The information provided in this field will be used by IRAS for statistical analysis only.

      Pre-filled Amounts

      From YA 2018, to improve companies' e-Filing experience, the following amounts will be pre-filled:

      • Unutilised Capital Allowances brought forward
      • Unutilised Losses brought forward
      • Unutilised Donations brought forward
      • Current year Approved Donations

      The amounts are pre-filled for the companies' easy reference. You are advised to verify the accuracy of the information. In case of any discrepancy with the details (i.e. the companies' carried forward amounts in their own records differ from the pre-filled records), you may update the pre-filled sections in the relevant Boxes under "Company's Declaration" (with the exception of donations).

      The 250% deduction for donations is granted based on information obtained from the Institutions of a Public Character (IPCs). You can view details of the current year approved donation amounts in the "View Donations" e-Service.

      If the company has made an approved donation, but it is not reflected in the "View Donations" e-Service at, it may be due to:

      1. Differences in receipting date - The IPC may have recorded your donation in a later financial period and a deduction would be accorded in the corresponding YA.
      2. You did not provide your company's Unique Entity Number (UEN) to the IPC. Please update your donation record with the IPC and IRAS will amend your assessment when we receive the updated record.

      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 the filing due date. You can access the draft anytime till the filing due date and make the necessary amendments before you submit your Form C-S. Companies/ tax agents who need to present the completed Form C-S to relevant personnel/ clients prior to submitting the Form C-S to IRAS may utilise the “Save Draft” function and print out the completed Form C-S at the “Confirmation Page”.


      If you remain inactive on your local machine for more than 15 minutes, the system will prompt you to respond within 2 minutes. If there is still no activity within 2 minutes, you will be logged out of automatically.

      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 the relevant financial period under 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 2020 and YA 2021). 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 2019. 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 2019 to 31 Dec 2020.

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

      YABasis Period
      2020 (1st YA)15 Jul 2019 - 31 Dec 2019
      2021 (2nd YA)1 Jan 2020 - 31 Dec 2020

      In this case, Company A has to attribute its adjusted profit/ losses before other deductions to YA 2020 and YA 2021 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 2019 to 31 Dec 2019 [YA 2020] and the period from 1 Jan 2020 to 31 Dec 2020 [YA 2021]).

      Once the adjusted profit/ losses before other deductions has been attributed to YA 2020 and YA 2021, Company A will need to complete the line items for YA 2020 and YA 2021 in the e-Form C-S accordingly.

      For more information on YA and basis period for new companies, please refer to Attribution of Profits/ Losses for New Companies.

      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 Form C-S/ Form C-S (Lite):

      Frequently Asked Questions (FAQs)

      For more details on e-Filing of Form C-S, please refer to our FAQs (PDF, 390KB).

      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)