How to File Your Tax Return Online

The deadline for filing your tax return online is the 31 January and in this guide, I’ll walk you through filling it in so you can beat the HMRC deadline.

Who Needs to Complete a Tax Return Online?

There are a number of reasons that HMRC expect you to lodge a tax return, the main one being they know you have received income that you need to tell them about and maybe pay tax on.

Many people in the UK do not need to complete a tax return because their employer handles all their tax calculations and payments on their behalf. This is known as the ‘Pay as You Earn (PAYE) System’.

Others may be able to avoid completing a tax return because they:

  • Receive income of less than £1,000 like from eBay, babysitting, rent (the £1,000 Trading and Property Allowance);
  • Rent a room in their own home for less than £7,500 per tax year;
  • Have less than £1,000 for basic rate taxpayers or £500 for higher rate taxpayers in savings (Personal savings allowance);
  • Have a business HMRC classifies as a hobby.

If HMRC has sent you a request for a tax return then they probably think you are earning an income that you need to pay tax on.  That includes people who are:

  • Self-employed;
  • Landlords;
  • Receive dividends;
  • Receive bank interest;
  • A Company Director;
  • Earning more than £50,000 a year (or someone in their household is) and receive child benefit.

If you have received a request from HMRC to complete a tax return but feel you don’t meet the criteria to need to do so, call them on 0300 200 3310 to discuss your situation and ask if they can withdraw the return.

When Do You Need to Complete Your Tax Return?

The deadline for filing your tax return online is 31 January, following the end of the tax year. One return covers one tax year.  So your 2019/2020 tax return is due by 31 January 2021.

A tax year runs from 6 April to 5 April.

There are strict penalties for failing to file your tax return on time, which can increase the longer you leave it. You may be able to appeal against penalties if you have a reasonable excuse.

You can choose complete a paper tax return instead of doing it online, but you’ll need to do this by the end of October.

What is a Short Form Tax Return?

If your business turnover is £85,000 or less, you’ll be able to complete a short form tax return which requires less information than the full one.

It’s aimed to make reporting taxes quicker and easier people who have more simple tax affairs.

If you are eligible to fill this return in, HMRC will automatically present you with this return when you login online.

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.

So for your 2019/2020 tax return, you’ll need information for 6 April 2019 to 5 April 2020.

Here’s a list of the things that are generally required to (if something on the list below doesn’t relate to you, ignore it):

  • Government Gateway Login and Password, also known as your Personal Tax account. If you have lost your user ID or password, then here’s how you can retrieve them.
  • 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 including business bank statements, invoices you have sent to your customers, invoices you have paid
  • Rental income and expenses including managing agents statements, invoices for anything you have paid for mortgage statements showing mortgage interest paid
  • Previous years tax return and details of any tax losses
  • Details of any other income you have received
  • If you received any other taxable income like the sale of shares, land or property.

Once you’ve got all your information together, you’re ready to start filling in your tax return online.

How to File Your Tax Return Online

You’ll need to log into your personal tax account on the HMRC website to start filing your tax return online.

Once you’ve logged, you need to find your tax return online and then work through each of the sections.

You’ll only need to fill out the sections that are relevant to you.

I’ve put together separate guides to help you complete each section:

Where to Find Your Self-Assessment Tax Return Form Online

Here’s how to find your tax return online, in case you are not sure if you have the right form in front of you or are unsure where you need to find it.

The “Tell Us About You” Section

The “Tell Us About You” section contains your personal details. This section is your chance to check HMRC have the right information about you and make any corrections necessary.

The “Tailor Your Return” Section

The “Tailor Your Return” Section is made up of three pages. It allows HMRC to get to know you and lets you remove sections of the tax return that are not relevant to you.

The “Fill Out Your Return” Section

The “Fill in your Return” screen contains a list of the sections that you need to complete. The sections included will vary person to person, depending on which parts of the tax return they need to fill out.

The “Employment” Section

You should fill in the Employment page if you were employed, either full-time, part-time or casual basis. You also need to fill it out if you received income as a Company Director or held an office. Fill out a separate employment section for each job, directorship or office you hold.

The “Self-Employment” Section

You only need to complete the self-employment section if it applies to you. That’s reasons like you work for yourself, are a sub-contractor under the CIS scheme or a registered Foster Carer.

Class 2 National Insurance Contributions

If you are self-employed, you’ll be presented with the Class 2 National Insurance Contributions page of your tax return.

The Self-Employment Section for Foster Carers

A step by step guide for Self-Employed Foster Carers to completing the self-assessment tax return, working out taxable income and claiming all the tax allowances they are entitled to.

Completing the Tax Return for the High-Income Child Benefit Charge

If you earn more than £50,000 a year and claim child benefit, then you may need to pay some or even all of it back, with a self-assessment tax return.

Underpaid Tax and Other Debts

This section confirms details of any underpaid tax that has been collected through your PAYE code if you were employed by someone.

Overpaid Tax

If you think you have paid too much tax and are due a refund, then you’ll need to let HMRC know where to send the money to.

If You Have Not Paid Enough Tax

If you are submitting your tax return before 30 December and are employed you can elect to pay any outstanding tax through your PAYE code.

Adjustments to tax due

In specific circumstances you can increase or decrease the amount of tax that is due on your tax return, changing how much tax you pay.

Any other information

If you need to let HMRC know any other information about your tax return and the figures you have used, then you need to enter it here.

Check Your Return & View Your Tax Calculation

You’re nearly at the endpoint. You’ve completed your tax return but now is your chance to check it and review your tax calculation.

Save your return

Everything is complete but keeping a copy of your tax return is advisable.

Submit your return

It’s the final step, to submit your tax return to HMRC.

How Early Can You Submit Your Tax Return?

You can submit your tax return at any time from the end of the tax year. In fact, the sooner the better so that you give yourself plenty of time to fill out your return. It can wake a while to complete your return, depending on how complicated your affairs are, so you’ll be able to do a little at a time.

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.

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 the bank details are:

Sort codeAccount numberAccount name
08 32 1012001039HMRC Cumbernauld
How Do I Pay My Self Assessment Tax Online?

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.

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.