DIN It: IRAS Document Identification Number Explained

3 min read

A Document Identification Number (or DIN) is a small but compulsory thing when filing your tax reports to IRAS — Inland Revenue Authority of Singapore.

When you need it, how to get it, what to use it for?  Your accounting company in Singapore already has the answers. However, it may still be useful to understand how your tax filings work. So below we explain everything you need to know.

What is DIN?

DIN is a unique number code. IRAS generates a new DIN for your company every year to identify each income tax return you submit. DIN is required only if you paper-file your tax return.

The filing goes through Form C-S/C, and a company’s DIN is to be found on this form for every specific Year of Assessment (YA) period.

DIN is a set of letters and figures, here is an example of one: SC 206 16264567890 023.

IRAS made e-filing of the Form C-S/C compulsory in 2018, planning to fully switch to the system step by step by 2020.

Year of Assessment Companies obliged to e-file tax returns
2018 onwards Companies with over $10 mln revenue in YA 2017
2019 onwards Companies with over $1 mln revenue in YA 2018
2020 onwards All companies

IRAS sends companies a notification letter about the Form C-S/C by May each year starting from the second year of incorporation. Companies must file their Income Tax Return by 30 November if they still file it in paper and by 15 December if they do that online (e-filing) in the year following the financial year end. So, you have 11 months between the time of closing of the accounts and filing the tax with the government.

Company’s financial year end Period covered in the accounts Year of Assessment Paper-filing due date E-filing due date
31 December 1 January 2019 to 31 December 2019 2020 30 November 2020 15 December 2020
31 July 1 August 2017 to 31 July 2018 2019 30 November 2019 15 December 2019

How to get a DIN?

DIN is issued after your Form C-S/C is issued.

When you e-file your taxes, you log in to IRAS myTax portal and choose “File Form C-S / C” —  the DIN will be provided automatically once you do a filing through the portal. You don’t see the DIN number in this case, as it is generated and identified electronically.

How to get your DIN through the IRAS website if you file paper returns:

  • select the YA (the service offers to see DINS for this YA and two previous ones);
  • enter your tax reference number;
  • type in the verification code;
  • get your DIN.

You can get your DIN on IRAS website


If you are a tax agent, you can get DINs for up to 10 clients in one search.

When you are not able to get a DIN

  1. It’s been less than 2 years since the company was incorporated. Most of the newly incorporated companies don’t start operations and get profits during this period, so IRAS doesn’t expect you to close your first set of financial statements (like profit & loss, balance sheet, etc.) during this time. So, they don’t issue Form C-S/C for you and don’t send you a notification letter about it. If you start a business and get some profit in these 2 years, you must e-file your income tax return through your company’s IRAS account yourself.
  2. A company has been granted a waiver to submit the income tax return. It happens when your company becomes Dormant. You can find what you need to get this waiver in Osome’s guide through Dormant companies in Singapore.
  3. Form C-S/C for a particular YA has already been filed. To find out the status of your income tax return, you should also check it out in your IRAS account.
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