Guidance on Completing Form C-S/ C

Guides to complete the Corporate Income Tax Return (Form C-S/ C) online. Companies are required to e-File their Corporate Income Tax Returns.


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) (PDF, 401KB)
• “Update Corporate Profile/ Contact Details” User Guide (tax agent) (PDF, 439KB)

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

Please e-File Form C via together with the tax computation, financial statements, detailed profit & loss statement and other supporting documents.