7 min read

Last minute tips for filing your self-assessment tax return

Andrew Hagger
19 January 2018

Don’t panic - there’s still time to meet the online tax return deadline and we’re here to talk you through the process.

Don’t worry if you’ve yet to tackle your online self-assessment tax return, all is not lost. There’s still time to meet the 31st January deadline.

Doing your taxes can seem like a very daunting and complex job, especially with so much detail to wade through on the official government website. So, if you’ve been putting it off, or just need a bit of guidance, we’ve put together a step-by-step guide to filling it out, mistake free.

When is deadline day?

The key is to complete your returns and make payment by midnight on 31st January. If this is the first time you’ve filed your taxes you need to register and wait up to 10 working days to be sent an online activation code.

If you miss the deadline there's a £100 late payment fine, and further fines and interest to pay the longer you leave it. If you do end up having to pay the fine be aware that HMRC no longer accepts payment by credit card so you’ll need to use a debit card.

Who does this apply to?

Your return gives the tax authorities (HMRC) details of everything you’ve earned in the last tax year (6th April 2016 to 5th April 2017) in order to calculate how much tax you owe.

If your income comes entirely from wages or a pension there’s no need to fill in the forms as the tax will have already been taken care of. But you’ll need to take the DIY approach if:

  • You’re self-employed or director of a company

  • Getting an income of £10,000 or more (before tax) from any savings or investments

  • You live abroad and receive an income from the UK

  • You receive an income from abroad

  • Your total income exceeds £100,000 for the year

  • Your untaxed income is £2,500 or more (for example from renting out a property, cash-in hand jobs or from tips)

You can see a full list here for more information.

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Where to start

Completing your tax return is far easier (and much quicker) if you have all the necessary financial info to hand before you start. So, before you sit down at your computer, take a deep breath, grab a cup of coffee and the following paperwork (for the period 6th April 2016 to 5th April 2017):

  • Your P60 and any payslips

  • Your National Insurance number and record of National Insurance contributions

  • Bank statements (personal and business) and credit card statements for the tax year

  • Any company accounts for info on your income and expenses

  • If your filing taxes for your own business, you'll need a list of company assets and liabilities (you can find this on your balance sheet)

  • Details of any savings interest and investment income (you can find this on bank statements or you can get a certificate of interest from your bank to get it all in one place)

  • Your pension statement for details of any personal pension contributions you’ve made.

Before you start working your way through the forms, print off a copy of the Tax Return notes form (SA150). It’s a handy document to have by your side, if there’s anything you’re not sure about. It makes it clear what needs to go in each box on the form.

Now you’re ready to start.

It may seem like a lot but try not to get overwhelmed. The online process actually makes it much easier. You don’t have to complete the form in one go as you can save your tax return at any time, picking up where you left off.

HMRC’s system will react to the answers you give as you input them. This might mean, for example, that sections that are not relevant to you are removed. And if you make an obvious mistake, HMRC’s software is quite clever and should highlight this.

Also, when typing in the figures on your return, the online help offers reminders about where you can find the information to fill in particular sections – such as your P60 or payslips.

Filling in the details

Next, it’s down to the nitty gritty of filling out the online returns. All the forms you need can be found here.

If you’re self employed you’ll have two forms to fill out.

The first is the standard tax return form (SA100) which covers your personal tax return and includes details of the following:

  • Your employment
  • Any income from savings or investements interest and dividends
  • Capital gains summary
  • Your income from pensions, annuities or state benefits.

This is also where you can make sure you're getting any tax relief you're eligible for. So you'll be asked to list details of your pension contributions and any charitable donations you've made. If there's any allowances that you need to claim, such as Blind Person’s, Marriage, Student Loans or Child Benefit, you can also do this in your return.

The second form is your self-employment return (SA103) which covers the details of your self-employment:

  • You'll have to share your business name, address and the income you've earned. This is so that the tax office can work out how much you owe in taxes and national insurance contributions.

  • You may have to provide a balance sheet to show details of what you own and what you owe.

On this form you can make sure you're claiming back any tax you're owed from things like allowable business expenses (this might include office costs, utility bills or travel expenses). You can also claim tax allowances for vehicles and equipment if you're eligible.

For both your personal and business tax, the exact amount of tax you owe will be worked out automatically, so no need to reach for the calculator.

Need some help?

If you get stuck there is a series of useful Self-Assessment YouTube videos to get stuck into.

You can also call the Self-Assessment helpline - it’s better to get in touch sooner rather than later as they get very busy near the deadline.

Once you’ve submitted your form and payment you can relax – until next time. Maybe put a note in your diary for September/October to get next year’s return in, to save any last-minute stress.

by Andrew Hagger

Andrew spent more than 30 years working for the biggest names in finance before becoming a respected personal finance commentator and journalist. He's written these article especially for ClearScore.

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