Tips on e-Filing Form C

CorpPass is the only login method for online corporate transactions with the Government. You must first be authorised via CorpPass before you can log in to IRAS digital services. Follow the Step-by-Step Guides on how to register for CorpPass.


Before e-Filing Form C

Important Notes:

  1. Ensure that you have been duly authorised by the company as an "Approver" for "Corporate Tax (Filing and Applications)" in CorpPass.
  2. Ensure that you have the company's tax reference number, your CorpPass ID and CorpPass password. 
  3. Download and install Adobe Reader XI (i.e. Version 11) or higher for Form C (Upload).
  4. Uncheck the security setting of Adobe Reader if you are unable to open the Form C (Upload) after installing the Adobe Reader XI (i.e. Version 11) or higher. Refer to Question 49 of the FAQs (PDF, 1.15MB) for instructions.
  5. Set aside at least 30 minutes to complete this electronic tax return.
  6. Get ready the following documents in softcopy for submission to IRAS:
     Type of Documents and Maximum File SizeWho needs to submit? 

    Form C (Upload)

    (Maximum file size: 4MB)


    (To be discontinued from YA 2021)  

    For companies who are using Form C (Upload) to e-File.

    Paper submissions of the YA 2020 Form C (Upload) will no longer be accepted.

    Please note that the Form C (Upload) will no longer be available from YA 2021. You are strongly encouraged to start filing the Form C using the Online Form C now. 

    Companies/ tax agents who need to present the completed Form C to relevant personnel/ clients prior to submitting the Form C to IRAS may utilise the “Save Draft” function and print out the completed Form C at the “Confirmation Page”.

    Audited/ Unaudited financial statements

    The financial statements (including notes to the financial statements), prepared in compliance with the Companies Act, must be accompanied by the Directors' Report and Statement by Directors.
    (Maximum file size: 4MB)

    (1)Please refer to ACRA's website on how to prepare your financial statements in XBRL format.
    (2)A dormant company is one which did not carry on business and had no income in the basis period.

    All companies, except

    • those that have filed a full set of financial accounts with ACRA in XBRL format(1); or
    • those which are dormant(2)
    Detailed profit and loss statement. This can be filed together with either the audited/ unaudited financial statements or tax computation and supporting schedules.All companies, except those which are dormant 

    Tax computation and supporting schedules

    You may wish to use the Basic Corporate Tax Calculator to prepare your tax computation.

    (Maximum file size: 4MB)

      All companies, except those which are dormant

      Revised tax computation(s) for prior Year(s) of Assessment (YAs)

      Example: Company claims current year Capital Allowances/ Losses against assessable income of the immediate preceding YA and submits a revised tax computation for the immediate preceding YA

      (Maximum file size: 4MB)

        Only companies submitting revised tax computation(s) 

        Research & Development (R&D) Claim Form (YA 2018 and before) (PDF, 187KB) 

        Research & Development (R&D) Claim Form (YA 2019 and onwards) (PDF, 234KB) 

        (Maximum file size: 2MB)

          Only companies claiming tax benefits on R&D expenditure 

          Declaration Form (PDF, 93KB) for the purpose of claiming Writing-Down Allowances for Intellectual Property Rights (IPRs) under Section 19B of the Income Tax Act

          (Maximum file size: 2MB)

          Only companies claiming Writing Down Allowances for IPRs 
        • Ensure that the softcopy documents are in pdf format. If not, convert them to pdf file format using software convertor (e.g. PrimoPDF).
        • Ensure that the hardcopy documents are scanned into pdf files and the images are clear.
        • Use font size of at least 11 for your attachments.
        • Choose the recommended resolution of 100dpi black and white if you need to reduce file size of attachments.

        e-File Form C 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 its staff or a third party (e.g., tax agent) as an "Approver" for "Corporate Tax (Filing and Applications)" in CorpPass before they 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 Matters; and

            • Key in your Organisation Tax Ref No, followed by your CorpPass ID and CorpPass password.

            (ii) If you are logging in as a tax agent of the company:
            • Select Client Tax Matters; and

            • Key in your Tax Agent Tax Ref No, followed by your CorpPass ID and CorpPass  password.

          Step 3: Submit the Completed Form C Online

          1. Click on Corporate Tax and select File Form C-S/ C.
          2. Select the Year of Assessment you are filing, followed by Form Type:

            Online Form C
            • Complete the Form
            • Click to Confirmation Page to verify that the information declared is correct. Thereafter, complete the Declaration and fill in Details of Filer & Contact Person.
            • Click on Submit Document to upload the relevant documents.
            Form C (Upload)
            • Complete the Form C (Upload). No signature is required in Part IV Declaration.
            • Save the duly completed Form C (Upload) in your local drive and upload the file and the relevant documents to myTax Portal. Do not upload a scanned or printed copy of Form C or Form C-S.
          3. Click on Submit to IRAS.
          4. You will receive an instant acknowledgement upon successful filing.

          For more detailed guides on e-Filing Form C:

          Points to Note when e-Filing

          Filing Deadline

          The annual filing deadline for Form C is 15 Dec for YA 2020 and 30 Nov from YA 2021 onwards.

          Online Help

          Please click on the iHelp icon < i2> should you require on-the-spot guidance as you e-File the Form C.

          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
          • Unutilised Investment Allowances brought forward 

          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 Institutes of 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 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. Companies/ tax agents who need to present the completed Form C to relevant personnel/ clients prior to submitting the Form C to IRAS may utilise the “Save Draft” function and print out the completed Form C 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 statements covers a period of more than 12 months from its date of incorporation, please indicate the relevant financial period under General Info.

          In the subsequent pages, you will need to:

          • Attribute the company's adjusted profit/ losses to two Years of Assessment (YAs)* (i.e. YA 2019 and YA 2020); and
          • Complete the fields required for two YAs in the Form C. This is because the basis period for each YA should generally not exceed 12 months.

          * 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.

          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 of receipt. The same acknowledgement will also be available at under the "View Corporate Tax Notices" e-Service.

          Detailed Information on Completing Form C

          User Guides

          Detailed user guides for Online Form C:

          Detailed user guides for Form C (Upload):

          Frequently Asked Questions FAQs

          For more details on e-Filing of Form C, please refer to our FAQs (PDF, 1.25MB).

          Contact Us

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

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