Self Assessment Tax Return

A Complete Guide to the Essentials of the HMRC Self Assessment Tax Return

While running your business you must have observed that while paying salaries to your employees their taxes get deducted automatically. But did you experienced that in your case when you earn profits? The answer is no. That does not mean you don’t have to pay taxes on your income. HMRC has created a self assessment tax return system through which you can declare your income, expenses and tax liability, plus pay your taxes starting from 6th April to 5th April.

To file tax returns, you will have to follow the below-listed steps:

  • ∙Apply and get a unique taxpayer reference (UTR) to register for self-assessment. The UTR is a 10-digit number that acts as an identifier for tax purposes for individuals and entities.
  • ∙Always keep your accounting records ready. You will have to focus on bookkeeping or recruit a full-time accountant to do it for you. In any case, you will have to keep your accounting records properly. If you cannot recruit or handle the accounts, you can entrust this responsibility to CoxHinkin’s bookkeeping services.
  • ∙Do your income tax calculation, including your taxable income and tax liability. Under the taxable income comes non-saving, saving, and dividend income. Non- saving income comprises employment income, trading income from self- employment, and property income.
  • ∙Then, you can file your self assessment tax return and pay your tax bill.

Who Requires HMRC Self Assessment?

We have placed people who would require HMRC self assessment tax return into multiple groups which we have listed down below. Let’s go through them in detail.

  • Self-Employed Individuals: For those who are running a business by themselves or in partnership are required to file a self-assessment tax return. Under it, income source, expenses, and tax owe must be declared. Nevertheless, those who earn less than 1,000 GBP are not required to a self assessment tax return.
  • Landlords: Even property earning such as rent earned by property owners comes under the ambit of self assessment tax return and must be declared.
  • Company Directors: Being a company director is subject to great responsibilities and a good pay. Certainly, the income earned from this position is required to be disclosed in a self assessment tax return.
  • High-Income Individuals: We are happy for you if you are earning good but do remember that if you are earning more than 1,50,000 GBP then must file a self assessment tax return. It would be applicable only if the income is not taxed at its source.
  • Receiving Foreign Income: Earning income from outside while being a resident of UK makes you liable to self assessment tax return.
  • Complex Tax Affairs: If your financial affairs are far more complex, you must file a self assessment tax return. You may have such complex situations only if you have multiple income sources.

What is Required for Self Assessment Tax Return?

In order to do a self assessment tax return successfully you will need to furnish certain documents and information. These documents and information will be used by the HMRC during the self assessment tax return process. Wondering what information and documents will HMRC ask from you? Well, we have made an effort to list it down below.

  • Personal Information: Keep your personal information ready with you that includes your address, date of birth, UTR, phone number, and national insurance number.
    Details of Your Income: Be ready with your income details because HMRC will be interested in it. The records of income and expenses from your business, or any other income sources must be readily available and provided to the HMRC.
  • Tax Credits and Deductions: While running your business you may be liable to tax deductions and credits and these are taken into consideration by the HMRC. Therefore, you are required to share the information of your tax credits that come under the construction industry scheme to the HMRC.
  • Records and Documentation: Keep your original records such as income slips ready because HMRC will surely ask them in order to verify your income sources. Make sure your records are in right order.

When Do I Need to File My Tax Return?

You have two options, if you are interested in doing the payments offline then the papers must be submitted on 31st October before midnight following the end of tax year. If you want to file it online then the deadline for submission is January 31st.

How to File a Tax Return?

Once you have gathered all the details of your income and expenses, you can start filing your tax return. The main form is called SA100, and we will explain the different section included in it.

Starting Your Tax Return

  • ∙Your personal details

What Makes Up Your Tax Return

  • ∙Employment
  • ∙Self-employment
  • ∙Partnerships
  • ∙UK property
  • ∙Foreign income
  • ∙Trusts
  • ∙Capital Gains Tax summary
  • ∙Residence, remittance basis etc
  • ∙Additional information


  • ∙Interest and dividends from UK banks and building societies
  • ∙UK pensions, annuities, and other state benefits received
  • ∙Other UK income not included on supplementary pages
  • Tax Reliefs
  • ∙Paying into registered pension schemes and overseas pension scheme
  • ∙Charitable giving
  • ∙Blind Person’s Allowance

Finishing Your Tax Return

  • ∙Tax refunded or set off
  • ∙If you have not paid enough tax
  • ∙If you have paid too much tax

Any Other Information

  • ∙Signing your form and sending it back

Once you start filling in the details, you will encounter different questions. Based on the answers, you will reach different sections, tailoring the tax returns according to your circumstances.

Things That Minimise Your Taxes

Before settling your tax return, make sure you have taken advantage of common reliefs that can be used to reduce your tax bill. Here is a list of certain allowances:

  • ∙Marriage Allowance
  • ∙Blind Person’s Allowance
  • ∙Dividend Allowance
  • ∙Savings rate band
  • ∙Capital Gains Tax Allowance
  • ∙ISA Contributions
  • ∙Pension Contributions
  • ∙Enterprise Investment Scheme (EIS)/SEIS
  • ∙Gifts and Inheritance
  • ∙Rent-a-Room Scheme

How to Pay Your Tax?

By now you must have gained valuable information on self assessment tax return, who needs self assessment, what is required in it, how to file, and how can you reduce your taxes. Now, we will explain how to make the payments.

Payments on Account: After the self-assessment you can make payments two time in a year i.e., on Jan 31st and July 31st. These are advancement payments towards your tax bill for the current year.

Final Payment: Final payments can be done on 31st January which is also the end of the tax year. On this date all the outstanding liabilities for the tax year must be cleared.

Payment Methods: There are various payment methods through which you can pay your taxes among them the most reliable is to go to a HMRC website and do the payments online. There are various options in the website such as direct bank transfer, debit or card. Furthermore, there is an option to make direct transfer from your bank account to the HMRC. It’s important to note that late payments will lead to penalties and interest.

Remember Your Reference Number: Never forget your 10-digit UTR number which is unique to your account. The number ensure that all the payments made by you are correctly credited to your tax liability.


We hope that we have been able to explain self assessment tax return in the simplest terms. Ourmain goal was to make you aware of its importance and how you can keep the records and information ready for evaluation by the HMRC. We have also made the effort to explain how payment of taxes can be made.

However, we understand that no matter how much we simplify things for you, the process will take time and effort. Any mistakes in providing information or documents will lead to penalties and loss of reputation. Hence, handing over such a complex task to a professional accountant from CoxHinkins will be wise.

CoxHinkins also offers year-end, payroll, bookkeeping, management accounting, and VAT services, to name a few. Our accountants are well-trained in Xero, QuickBooks, and Sage accounting software, and we have designed our services to give your business an edge in the market, thus saving you time to invest in other important tasks. We can connect at your convenience by phone or online meeting to discuss our services in detail.


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