How to Fill In Your Tax Return Online

In this step-by-step guide, you’ll find everything you need to know to fill in your tax return online and beat the HMRC deadline.

Not sure whether you need to fill in a tax return? Use this guide to help you work out whether you need to send one to HMRC or not.

When is the Tax Return Deadline?

The deadline for filing your tax return online is 31 January, following the end of the tax year. A tax year runs from 6 April to 5 April. So your 2019/2020 tax return is due by 31 January 2021.

There are strict penalties for failing to file your tax return on time, which increase the longer you leave it and even though may be able to appeal against penalties if you have a reasonable excuse, HMRC isn’t very generous with what they consider reasonable.

You can choose to complete a paper tax return instead of doing it online, but you’ll get this into HMRC earlier, by the end of October. And if you want to pay any tax you owe through your PAYE code, the deadline is the end of December so leave enough time to make arrangements to change your tax code.

How Early Can You Send In Your Tax Return?

You can send in your tax return at any time once the tax year ends, but don’t worry you won’t need to pay your tax until the 31 January. Some people prefer to get it done as soon as possible so they have plenty of time to fill in their tax return or they know they are due a tax refund and want to get the money back.

How to Find Your Tax Return

You tax return will appear in your .GOV account automatically once you have registered as self-employed. You can login via your personal tax account to find it.

Here’s what to do if you’ve lost your user ID or password

What You Need Before You Get Started Completing Your Tax Return

Getting all the documents you need ready in advance will make completing your tax return quicker and easier. You’ll only need documents that are relevant to the tax year you are filing your return for. Here’s a list of the things that you may need:

  • Personal details including your UTR number, national insurance number and bank details if you are expecting a tax refund;
  • Partners Information if you want to claim marriage allowance;
  • Employment Information;
  • P45 or P60 if you were employed either full-time or part-time during the year;
  • P11d if you were employed and received a taxable benefit like private medical insurance or a company car;
  • Dividend certificates;
  • Bank interest certificates;
  • Student loan statements;
  • Pension statements and pension contributions;
  • Self-employment income and expenses from your bookkeeping system;
  • Rental income and expenses including managing agents statements, invoices for anything you have paid for and mortgage statements;
  • Previous years tax return and details of any tax losses;
  • Details of any other income you’ve received.

How to Fill in Your Tax Return Online

Tell Us About You

You’ll need to start completing your return by filling out the “Tell Us About You” section. This section is your chance to check HMRC have the right personal information about you and for you make any corrections necessary, like a change of address. It will be pre-populated if HMRC has any of the information on their system already, but it still pays to check that everything is correct.

Some boxes like phone number and email address are optional, so it is up to you whether you want to provide it. But it can be useful to add them in case HMRC need to contact you. Make sure that you:

  • Check all your personal details;
  • Ensure the box is ticked to say you are UK Resident;
  • Tick the box if you are entitled to blind person’s allowance;
  • Enter information if you are making student loan repayments, the type of plan you are on and whether you are employed or self-employed.

Once completed you’ll move onto the tailor your return section where you tell HMRC about your different earnings and remove any sections of the tax return that are not relevant to you.

Tailor Your Return

You’ll need to work your way through confirming what types of income you have received for example self-employment or dividends and the income tax reliefs you’ll planning to claim to reduce your tax bill.

The Tailor Your Return Section

Once you have tailored your online tax return to your personal circumstances, it’s time to start inputting the numbers. You’ll notice that many of the sections have a cross next to it, the aim to get all ticks.

Employment Page

If you need to fill out the employment page, you’ll need to enter your income from your P45 or P60. If you had more than one employer during the tax year, then you’ll need to complete one of these for each employer. You’ll also be able to claim tax relief on expenses that you paid for but were not reimbursed by your employer.

The Employment Section

Self-Employment Section

You’ll be presented with the self-employment section if you work for yourself, are a sub-contractor under the CIS scheme or a registered foster carer.

The first thing you’ll need to do is calculate your business turnover because if it is less than £85,000 then you’ll be able to complete the short-form self-employment section, which requires less information. Next, you’ll need to have your business expenses ready and then decide what tax reliefs like capital allowances and loss reliefs you want to claim.

The Self-Employment Section

Self-Assessment for the High-Income Child Benefit Charge

If you or your partner earn between £50,000 and £60,000, including through self-employment, then you’ll need to pay back any child benefit you have received in the form of an income tax payment. You can choose to do this by electing to stop receiving child benefit payments or paying the high-income tax charge by filling out a tax return.

This charge claws back child benefits paid at a rate of 1% for every £100 you earn over £50,000. That means once your income reaches £60,000 you will not receive any child benefit.

Self-Assessment for the High-Income Child Benefit Charge

How Do I Pay My Self Assessment Tax Online?

You can pay your self-assessment tax bill online in a variety of ways including by direct debit, bank transfer and with a debit card. If you want to pay by bank transfer, then you’ll find the bank details on the HMRC website.

Whichever method you choose, make sure you use your UTR number as the reference for your payment so it gets allocated to your account correctly.

Alternatively, if your tax bill is less than £3,000 and you are employed, you can choose to pay your self-assessment bill through your PAYE code but you must have submitted your tax return by 30 December.

How to Pay Self Assessment Tax Through PAYE

How Long Does it Take to Get a Tax Refund After Self Assessment?

If you are due a tax refund, you’ll need to let HMRC know that you want a repayment and enter your bank details. Once this is done, it can take up to 4 weeks for HMRC to process your refund and send it back to you.

While I have made every attempt to ensure the accuracy of the contents of this guide, I cannot accept responsibility for any losses or penalties you may incur while following the contents. I have prepared the contents for a wider audience so you may need to seek additional assistance relevant to your own personal situation.

Anita Forrest
About Anita Forrest

Anita Forrest is a Chartered Accountant, spreadsheet geek, money nerd and creator of - the UK small business finance blog for the self-employed community. Here she shares simple, straight-forward guides to make self-employment topics like taxes, bookkeeping and banking easy to understand.