Guidance on Completing Form C-S/ C

Guides to complete the Corporate Income Tax Return (Form C-S/ C) online or via paper filing. All companies are encouraged to e-File your Form C-S/ C! Go paperless!

Before Completing Form C-S/ C

All companies need to prepare the following before completing the Corporate Income Tax Return (Form C-S/ C):

  • the audited/ unaudited financial statements,
  • tax computation and supporting schedules, and
  • other claim forms

For more details, please refer to Documents to Prepare when Filing Form C-S/ C.

If your company’s functional currency is not in “Singapore Dollar”, you have to inform IRAS by logging in to and updating it via the "Update Corporate Profile/ Contact Details" e-Service. You may refer to the following user guides for more information:

• “Update Corporate Profile/ Contact Details” User Guide (company) (1.21MB)
• “Update Corporate Profile/ Contact Details” User Guide (tax agent) (1.29MB)

Authorise Users for Corporate Tax Matters

The company must first authorise its staff or tax agent for "Corporate Tax (Filing and Applications)" in CorpPass before they can log in to e-File Form C-S/ C on behalf of the company. For assistance on CorpPass setup, please refer to Step-by-Step Guides.

Filing Form C-S

Filing Form C

e-Filing of Form C

You can e-File Form C in two ways:

ModesHow to e-FileSuitable for 

Online Form C


Available now 

Complete and file Form C online. Attach tax computation, financial statements, detailed profit & loss statement, other supporting documents and submit them to IRAS. All companies/ tax agents 

Form C (Upload)


Available now

Download and complete Form C (PDF format) on your local machine. No signature is required in Part V Declaration. When the Form C is completed and the file is saved in your local drive, upload it to myTax Portal and submit it together with tax computation, financial statements, detailed profit & loss statement and other supporting documents. Please upload the original Form C (PDF Format). Do NOT upload a scanned or printed copy of 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


Online Form C:

Form C (Upload):

Paper Filing of Form C


  • Strongly Disagree
  • Strongly Agree

Information is easy to understand.

Information is useful.

Information is easy to find.

Please email us if you would like us to respond to your enquiries.