A Guide to Completing & Filing Your Self Assessment Tax Return

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A Guide to Completing & Filing Your Self Assessment Tax Return

What Do I Need to Do & When?

As a self-employed individual, you must complete and file your self-assessment tax return with HMRC. You can do this online or by filing a paper tax return. The deadlines are:

Filing online - 31 January

Filing paper tax returns – 31 October

So, filing online gives you a little more time but however you choose to do it, don’t leave it until the last minute. Remember, if you miss the deadline, you may receive a fine.

What Information Do I Need to Complete My Tax Return? 

You will need the following income information when completing your tax return:

  • employment income (if you’re also employed)
  • dividends
  • partnership income
  • interest
  • rental income
  • foreign income
  • pensions contributions

You may also need the following:

  • Gift Aid
  • pension income
  • payment on account
  • redundancy lump payment or unemployment benefit
  • P11D
  • capital gains

It’s worth remembering that this information will be required to complete your self-assessment tax return so get into the habit of keeping it somewhere safe throughout the year and after the tax return has been filed... HMRC may ask to see your documents.

For the self‐employed, the key information is likely to be your income and expenditure details, so you should have all your invoices and receipts to hand. You will also need your bank statements so either download them or ask your bank in good time.

You’ll also need your unique taxpayer reference number, otherwise known as your UTR. You receive your UTR when you register as a self-assessment taxpayer.

If you need help with your records, you might want to consider hiring an accountant – also keep in mind that there’s accounting software available that can make keeping good records a breeze.

How to Register for Self-Assessment

You need to register for self-assessment at the gov.uk website, this will allow you to log in. If you have not used the online service before you will be sent an activation code in the post; this can take up to 10 days to receive.

The deadline for registering for self-assessment is 5 October in your business’s second tax year. 

The Step by Step Guide to Completing Your Self-Assessment Tax Return: 

Make sure the information you require is to hand, then log in to the gov.uk website, and you’re ready to fill in your tax return.

If you’ve kept good records it should be straightforward.

1. Check Your Personal Details 

Make sure your name, address and any other information are correct. You should do this throughout the self-assessment process

2. Fill in the Sections That Apply to You

HMRC’s system reacts to your details as you enter them. This means that as you fill in the form, it may remove sections if they’re not relevant.

3. Report on Your Income

You will need your sales invoices for this but if you have other forms of income such as property income or gains on investments you will need to enter this as well.

4. Add Your Tax-Deductible Expenses 

Use your expense receipts when filling in this section. If you are not sure, it’s worth taking a look at our handy guide to what you can claim as a self-employed tax-deductible expense.

5. Double-Check Your Return

If you need to you can save everything you’ve entered and come back to your tax return, which can be useful if you want to check your numbers. But don’t worry, if you notice an error once you have completed the return, you can change your tax return after filing.

What Happens Next? 

When you file the return, you should get a confirmation message and a reference number. HMRC will calculate the tax you owe, as well as the National Insurance contributions you need to pay. The deadline for paying your tax return is the same day as the deadline for filing.

Remember that most self‐employed people usually need to make a payment on account too, which can catch newly self‐employed people out – you should make sure you have enough set aside.

There you have it, our all-encompassing guide on completing & filing your self-assessment tax return. Tax can be complicated, and if you have any concerns at all we would always recommend you take a look at the gov.uk website. 

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