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Submit your Self-Assessment Tax Return to HMRC within minutes Self Assessment is a system HMRC uses to collect Income Tax. From this page you can calculate how much tax you owe and file your tax return with HMRC.

  • Easy to use recognised HMRC filing software
  • Detailed Income Tax calculation breakdown
  • Secure electronic link with HMRC
  • Free support by chat, email and phone
  Need to register for a Self-Assessment UTR first?

Filing your Self-Assessment Tax Return is as easy as 1 | 2 | 3

1. Answer a few questions regarding your income and expenses
We’ve simplified the filing process by creating a streamlined jargon- free tax questionnaire which includes useful tips for a step by step support. You’ll only be asked to answer questions relevant to your specific situation.

2. Submit and file your income tax return securely with HMRC
Online Filings self assessment filing software is recognised by HMRC meaning that it has been tested by HMRC and we hold an electronic link with them. Your return is filed instantly as soon as all necessary information is provided.

3. Get unlimited support throughout your filings from an experienced team
Our customer experience team is available promptly during office hours by chat, email and phone to smooth-out your filing experience, should you need assistance when using the software.

Our software supports a wide range of income sources

Employment types

  • Employment - SA102 Full/Short
  • Self-Employment - SA103 Full/Short
  • Property - SA105

Income types

  • Foreign Income - SA106
  • Capital Gains - SA108
  • Residency - SA109

From our blog

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What is a Tax Return?
8 Things to Know Before Filing

If you’re an entrepreneur, investor, or sole trader, chances are you’ve made an income that hasn’t been taxed yet. If this is the case, it’s important to report any untaxed income to HMRC so you can pay the correct amount of income tax and remain compliant. This is done by filing a self assessment tax return, commonly referred to as a tax return.

But what is a tax return, and how do you file one properly? We’ve simplified this process at Online Filings to provide you with everything you need before you send your first tax return.

1. What is a Tax Return?

Simply put, a tax return is a report of all the income you have earned that HMRC does not know about yet. If you’ve earned an income through wages, pensions or savings, the income tax will almost always be automatically calculated and deducted from your income before it’s even sent to you.

However, if you earn income in any other way, like freelancing, renting out a property, or earning foreign income, it will not automatically be taxed. Therefore, you must manually report it to HMRC using tax return software.

2. Who needs to file a tax return?

You do not need to file a tax return if your only source of income is your wages or pensions. These are automatically taxed by HMRC.

Anyone who earns income that has not been automatically taxed will need to file a tax return. For example, those who are self-employed as a ‘sole trader’ and earn over £1,000 (before any tax reliefs) will need to report their income to pay the correct amount of income tax. Partners in a business partnership will also need to file a tax return to declare the income or losses of the partnership.

Additionally, you might need to file a tax return if you are a:

  • Landlord
  • Airbnb Host
  • Investor
  • Foreign income earner
  • Freelancer
  • Crypto investor
  • Earning £1,000+ from a side gig
  • Earning £100,000+

3. What is the tax return deadline?

There are a few important tax deadlines to take note of before you file a Self Assessment. The tax year starts on the 6th April and finishes on the 5th April of the following year. Within that, here are the tax deadlines you need to know:

5th October 2021: Deadline to register if you’re a sole trader or self-employed, not self-employed, or registering a partner or partnership

31st October 2021 at midnight: Deadline to send paper tax returns (available until 2024)

31st January 2022 at midnight: Deadline to file your tax return online AND pay the tax you owe to HMRC

4. What do I need before I start?

There are a few things you need before you can file your tax return, starting with your ten-digit unique tax reference number (UTR). You will need to apply for a UTR if you do not have one. It’s important to have this done before you register with HMRC to file your tax return.

Receiving your UTR is done through the post and can take up to 10 working days or longer if you’re registering from abroad. Take this into account before you register and make sure you have enough time. You'll also need this unique tax reference number for every tax return you fill out in the future.

You can apply for your unique taxpayer number in just 10 minutes using our simple service. We will securely send your application to HMRC and ensure you receive your UTR through the post. Click below to get started.


Other important things to have before you fill out your tax return:

  • Your national insurance number
  • All untaxed income details (ie. rent payments, invoices, income from dividends and interest)
  • Records of self-employment expenses
  • Charity donations and gift aid forms
  • Any pensions eligible for tax relief
  • Your P60 and other records of income you’ve paid taxes on

Once you’ve collected all the necessary documents and reference numbers, you can begin your tax return.

5. How do I fill in my tax return?

What is the tax return process after you’ve got the necessary documents? Once you’ve got your unique tax reference number and the rest of your documents, you can start filling out the SA100 form. This is the main form in your tax return that nearly everyone will need to fill out.

There are 8 main sections. Make sure to read the notes and help sheets before you fill out each section:

  1. Starting your tax return: enter your date of birth, name, address, phone number, and NI number
  2. What makes up your tax return: Select which methods of income you’ve earned (e.g. dividends, pensions, rent, self-employment) so you know which supplementary forms to fill out
  3. Income: Declare the amount of all income you’ve earned including interest, dividends, pensions, annuities, state benefits, and any other UK income not included in the supplementary pages
  4. Tax reliefs: Tax reliefs: Declare all payments you’ve made into registered and overseas pension schemes, all of your charitable giving and whether you are eligible for Blind Person’s Allowance
  5. Student Loan and Postgraduate Loan repayments: If you are repaying student or post-graduate loans that are contingent on your income and due before 6th April 2021, declare the amount deducted by your employer
  6. High Income Child Benefit Charge: Fill out this section if your income is over £50,000, you or your partner got Child Benefit, and if your income was higher than your partner’s (if you have one)
  7. Incorrectly claimed coronavirus support scheme payments: If you incorrectly claimed any payments from an applicable HMRC coronavirus support scheme, let HMRC know here
  8. Marriage Allowance: If you would like to transfer £1,250 of your Personal Allowance to your spouse or civil partner to reduce the amount of tax they pay, you can do that here. Make sure to read the guidance and notes to find out if you’re eligible
  9. Finishing your tax return: You’re almost done! Declare any tax that’s been refunded or set off to you, if you’ve paid too much or too little tax, and your tax adviser’s information (if you have one), plus any other relevant information

The last step is to complete your form and any supplementary pages, then you can send it to HMRC. Alternatively, you can use this service to file your self assessment without worrying about any of the additional forms and have it submitted in minutes.


6. What Self Assessment forms do I need to fill out?

Depending on your methods of income, you may need to fill in additional forms - these are called supplementary pages. But what is the tax return supplementary page that’s relevant to you? The most common forms are:

  • SA200 Short Tax Return: this is a simpler version of the SA100. You will only need to fill this out if HMRC sends it to you. You can find guidance on this form here.

  • SA102 F/S Employment: If you’re an employee or company director, you’ll need to record your employment details and pay (from your P45 or P60) using this form.

  • SA103 Self Employment: If you’re self-employed and earning an income, you’ll need to use this form to provide the grand total of all income during the tax year (before expenses). You can view the full form here or view the short form here. You can find helpful notes for the full or short forms as well.

  • SA105 Property: If you’re a landlord or landlady, you’ll need to add the income you’ve earned from rented properties. You can do that here.

  • SA102M Ministers of Religion: If you’re a clergyman or minister of religion, record your employment income using this form.

  • SA104 F/S Partnership: If you are part of a business partnership, use the full form or short form to record any partnership income you’ve earned. Make sure to view the limits on income tax reliefs before you submit.

  • SA109 Residency: If you’re a non-UK resident or dual resident, record your residence and domicile status with this form. You can find help here.

  • SA106 Foreign Income: If you earn foreign income and gains, you can declare details of this income using this form. Access the form here and view helpful notes here.

  • SA107 Trust: If you’ve received income from a trust, settlement, or deceased person’s estate, you can record that using this form.

  • SA108 Capital Gains: If you’ve earned income from Capital Gains, or selling something that’s increased in value, you’ll need to declare your ‘disposal proceeds’ (net income) with this form. Fill in a separate disposal proceeds total for shares, securities, and properties - both residential and not. Make sure to utilise the notes here to help you.

7. How do I submit my Self Assessment when it’s finished?

There are a few different ways to submit your tax return. Submitting via HMRC’s website is an option, or you can submit a paper tax return. Please note, however, that these methods will be phased out by 2024 as part of HMRC’s Make Tax Digital (MTD) initiative, which endeavours to make tax affairs easier and more accurate for individuals and businesses. The best long-term method is using a Self Assessment tax return software like this.

This service quickly and accurately calculates an estimate of the tax you owe HMRC. Once you’ve calculated the amount, you can choose to register your self assessment, file and submit it directly to HMRC using our all-in-one service.

8. Lastly, how do I pay the tax I owe to HMRC?

You have multiple methods to pay your tax, but the most convenient is through bank transfer with your tax number (UTR plus the letter ‘K') as reference. To do this, start your Self Assessment payment and select the 'pay by bank account’ option. This will take you to your online banking account where you can approve the payment. It should be sent immediately but may take up to 2 hours to appear in your account.

The deadline to pay your tax is 31st January. If you still have payments on account from the previous tax year, you will need to pay that on top of this year’s tax.

Ready to file?

We provide a full Self Assessment tax return software with a detailed breakdown of your calculated Income Tax. When finished, we will securely submit your tax return directly to HMRC. Simply add some information about the income you’ve earned and we’ll do the rest.

In addition, we’ve intuitively designed this tax return software to be quick and easy with:

  • Jargon-free language
  • Simple instructions
  • Free support from business professionals

Ready to get started?

Who needs to register for Self Assessment
Before you can file a tax return, you will need a UTR number so HMRC can create account for you. Here are some of the people who might need to file:


You earn more than £100,000


Airbnb hosts

You earn more than £1,000 from a side gig


Crypto investors

You earn foreign income

Frequently Asked Questions

What are the reasons for me to file a tax return?

  • You are self-employed (a 'sole trader') and earned more than £1,000 in the previous tax year
  • You are a partner in a business partnership
  • You are a company director
  • You are renting out a property
  • You have taxable income from savings
  • You have investments
  • You receive dividends
  • You have a foreign income
  • You want to claim some Income Tax Relief
  • You have other non-taxed income at source
  • You have annual income of £100,000 or more before tax
  • You have capital gains or loss to claim

Why should you use an accountant to file your Self Assessment tax return?

An accountant will check your data to make sure you do not make any mistakes and you can ask them for advice regarding any queries. An accountant has experience in preparing tax returns and can help you identify tax regulations which apply to your situation.

Moreover, accountants have knowledge about the tax system and legislation which can add value to your tax planning. Furthermore, accountants can help you communicate with HMRC and help with any disputes (to help prevent legal action).

When does the personal tax year start and end?

The personal tax year starts on 6 April and ends on 5 April of the following year.

The last tax year started on 6 April 2021 and ended on 5 April 2022. This means that we are reporting income sources between those dates.

How do you pay Self Assessment tax?

We recommend paying your tax via bank transfer.

You would pay the bank account listed below:
08-32-10 - 12001039 - HMRC Cumbernauld

Your payment reference is your ten-digit UTR (Unique Tax Reference) number followed by the letter k at the end.

You can also log in to your HMRC account and pay via card.

How long do I need to keep my records for tax purposes?

You have to keep your records for at least 5 years from the January 31st submission date of the relevant tax year, as HMRC may request additional information in the future (for example, for auditing purposes).

Do you need to include ISA income on your tax return?

You do not need to declare any income on your ISA account as the income generated on those accounts are tax-free. This includes all types of ISA (cash ISAs, stocks and shares ISAs, innovative finance ISAs, Lifetime ISAs and Junior ISAs).

If you have reached 55 years of age and have taken out 25% of your personal pension pot as a lump sum, do you need to declare this?

When you reach 55, you can take up to 25% of your pension pot tax-free and it is separate from your personal allowance. Funds taken out of your pension pot up to 25% of your total pension pot do not need to be declared on your tax return.

How do you calculate capital gain or loss on simple personal assets disposal (not related to property)?

To calculate gain or loss simply deduct the disposal price from the purchase price. You can also deduct the cost associated with asset purchase and disposal.

When is the submission deadline for Self Assessment?

The deadline for paper submissions is midnight 31 October of the same year. For example, for the tax year ending on 5 April 2021 the deadline for paper submissions is 31 October 2021.

Nowadays people are filing their tax returns online. The submission deadline for online tax returns is midnight 31 January of the following year. For example, for the tax year ending on 5 April 2021 the deadline for online submissions is 31 January 2022.

What happens if you miss a deadline?

If you are late with your tax return submission you will be charged with penalty and interests:

  • If you miss the submission deadline you are charged a flat penalty of £100.
  • If you are 3 months late with the submission, a daily penalty of £10 per day for up to 90 days (maximum £900) is added to your initial penalty.
  • If you are 6 months late with the submission, you will pay an additional penalty of 5% of the tax due or £300 (whichever is greater).
  • If you are 12 months late with the submission, you will pay yet another additional penalty of 5% of the tax due or £300 (whichever is greater).

Separately, you will also be charged for late tax payments:

  • If your payment is late for more than 30 days you will be charged 5% of your tax.
  • If you are 6 months late with the payment, you will incur a penalty of 5% of the outstanding tax.
  • If you are 12 months late with the payment, you will incur an additional penalty of 5% of the outstanding tax at that time.

You are allowed to appeal against a penalty if you have a reasonable excuse.

What are the reasonable excuses to appeal against a penalty?

Reasonable excuse are excuses which prevented you from filing the tax return. Some examples of reasonable excuses are:

  • Death of a close relative
  • Hospitalisation
  • Issues with HMRC online services
  • Natural disasters (e.g. flood, fire, etc.)
  • Disability-related delays
  • Covid-19

Example excuses not accepted by HMRC:

  • Failure of a 3rd party submission
  • Failure to pay due to lack of funds
  • Not receiving HMRC reminders
  • Mistakes in tax return
  • You are allowed to appeal against a penalty if you have a reasonable excuse.

What happens if you make a mistake on your tax return?

If you made a mistake on your tax return, you can still make amendments even after submission. You have 12 months after the original submission deadline to file the amended tax return. For example, for the tax year ending 5 April 2021 you can file amendments by 31 January 2023.

What are Capital Gains Tax (CGT) exemptions?

Capital Gains Tax is a tax on the profit when you sell (or ‘dispose of’) something (an ‘asset’) that’s increased in value.

  • When you transfer your assets to your spouse or civil partner then you are not liable to Capital Gain Tax.
  • You may not be liable to Capital Gains Tax if you make a gain when selling personal items for less than £6,000.
  • You do not pay CGT on your car (unless used for business purposes).


From our business users

  • customer review
    4 reviews

    5 stars    Invited

    Very easy to use
    Very easy to use, quick clear confirmation e mail sent.

    8 days after first filing

  • customer review
    Lee Ratcliff
    1 review

    5 stars    Invited

    Excellent process for me.
    This process was extremely easy and something that I thought would be difficult, when I sent a question it was answered within hours and further more my registration was set up in 36 hours.

    3 days after first filing

  • customer review
    Katrina Stothers
    1 review

    5 stars    Invited

    Quick and simple
    Quick, simple and on line guidance is great.

    3 days after first filing

  • customer review
    Mark Thomas
    2 reviews

    5 stars    Invited

    First class service
    First class service, did exactly what was promised and even agree to refund initial fee if they could not deliver. thank you

    2 days after first filing