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A CWF1 form is something that you fill out when you’re self-employed. You use it to tell HMRC that you are earning money and need to do a Self Assessment. You can use it both to register or to re-register as a sole trader. Of course, you can also do all this online, but you would use this form if you prefer paper registration.  

What’s Self Assessment?

Self Assessment is the process by which you pay the taxes you owe to HMRC on untaxed income. If you work full-time as an employee, you pay your taxes directly from your salary. This method is called Pay As You Earn (PAYE). But when you’re self-employed, you earn money gross i.e. tax is not deducted from it. This means that you have to declare your earnings to HMRC yourself and do a tax return. 

And you need to do this by 31st January, the year after the tax year you’re paying for.

“Wait, what does that mean?!” you ask. Here’s an example:

You start trading in September 2023. This means you’re earning in the previous tax year – 2023/24 – which ran from 6th April 2023 – 5th April 2024. You need to pay your first tax bill by 31st January 2025. 

What’s on a CWF1 form?

When you fill out a CWF1 form, you have to provide the following details:

  • Name
  • Address
  • Business address
  • National Insurance number
  • Business details

Click here to fill in your CWF1 form with HMRC.

How does the CWF1 registration process work?

After you’ve submitted your CWF1 form, you’ll be given a Unique Taxpayer Reference (UTR) number, which you use to pay your tax return.

When do I submit?

If you’re registering with a CWF1 form, the deadline to submit is the same as the online deadline. You must register for Self Assessment by 5th October, no later than the year after you start trading.

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