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Completing your Self Assessment Tax Return

Download our checklist to help you complete your Self Assessment Tax Return for 2023-24

Documents and information required to complete a tax return

The type of information and documents that we need from you to complete your Tax Return depends on the types of income and gains you have received in the tax year and also some of the payments that you have made too. The following are the most common types of documents that we would require.

Employment Income (including some pension income)

  • Form P60 (year-end summary of tax and gross income).

  • Form P45 for any jobs you have left during the tax year.

  • Form P11 for any benefit in kind from employment e.g. use of car, van, medical schemes.

  • Payslips and particularly the last one of the tax year.

  • If you have made student loan repayments, they are shown on your Form P60.  However, student loan repayments are not shown on Form P45. This is why payslips are useful.

  • A list of tips or gratuities if not taxed through the normal wages and salary payroll system.

  • List of professional subscriptions.

  • List of expenses necessarily incurred in your employment e.g. business mileage or other amounts.


Rental income

  • A list of rental income and expenditure.

  • Additional information relating to repairs, replacements and improvements, as these amounts may not be tax deductible against rental income and may be classified as costs for the purposes of the calculation of capital gains tax in due course.


Savings and investment income

  • A list of bank, building society and other interest received. This can be extracted from bank statements, passbooks and tax deduction certificates. Most interest is now received without any tax deducted at source. However, this is not always the case, so be careful to check whether interest has been deducted at source.

  • A list of dividend income received. You should receive a dividend voucher. Sometimes these are provided towards the end of the tax year.

Social Security benefits

  • Letters from the Department for Work and Pensions (DWP) showing any amounts received during the tax year.  Not all state benefits are taxable. You may find this HMRC tax-free and taxable state benefits link helpful. Details regarding the amount of state pension is providing before the start of the tax year. Jobseeker’s Allowance will be shown on Form P45U or Form P60U.

  • Child Benefit received by the mother may be subject to the High Income Child Benefit Charge e.g. if someone in the household has personal taxable income over £50,000. This can apply to either you or your partner (not necessarily husband/wife/civil partner) if one of you receives Child Benefit for a child living with you and they contribute at least an equal amount towards the child’s upkeep. If you or your partner have income over £50,000 in a tax year, then some or all of the Child Benefit is repayable through the Tax Return. If your or your partner’s total income exceeds £60,000, then all Child Benefit received is full repayable. It does not matter if the child living with you is not your own child.


Self-employment income

  • A list of business income and expenditure for the tax or accounting year. We may have to prepare a full set of accounts for your business well before we start to prepare your Tax Return.

  • CIS tax certificates for payments received under the construction industry scheme.


Capital gains

  • Sale contracts, price and date of sale e.g. completion statement.

  • Purchase contract, price and date of purchase e.g. completion statement.

  • Costs of improvements or further purchases and dates e.g. invoices.

  • Associated legal and professional costs and disbursements of sale and purchase.

  • Probate or market value of gifts received in wills etc.

  • Contract notes for the sale and purchase of some assets e.g. shares.

  • For let residential property, details of periods of own occupation and letting where the property has at some stage been your main private residence, but has also been let to tenants.

  • Sales and purchase records for cryptoassets / cryptocurrencies (*)

Other income

  • Life insurance chargeable event certificates.

  • Details of any income you receive from a trust e.g. Form R185.

  • List of personal pension payments with personal pension plan certificates.


  • List of personal pension payments with personal pension plan certificates.

  • List of gift aid payments. Gift Aid means charities etc can claim tax on a donation.  Not all donations to charities are via Gift Aid. Other donation payments do not qualify and should not be put on the Tax Return.

  • EIS3 or EIS5 certificate if you invested in an Enterprise Investment Scheme.

  • VCT certificate if you invested in Venture Capital Trusts.

Cryptocurrency/cryptoassets (*)

Think you are not affected by tax cryptoassets  - think again!  See out blog article cryptoassets

Holders of cryptoassets should consider the potential capital gains tax implications. HMRC is keen to ensure that people fully understand that the following three common types of transactions are not tax exempt and may need to be reported on a Tax Return:

  • Paying for goods or services with cryptocurrency 

  • Selling cryptoassets for fiat money like £, € or $.

  • Exchanging one cryptoasset for another 

In all the above cases, these transactions will be disposals for capital gains tax purposes. Whilst the capital gain or loss may be small, they each add up. If the aggregate capital gains in a tax year exceed your annual exemption, currently £6,000 pa for 2023-24, then the gain or loss must be reported on a Self Assessment Tax Return, even if no capital gains tax is due.


For 2024-25, the annual exemption reduces to £3,000 pa. If the capital gain tax proceeds reporting limit of £50,000 is exceeded, the capital gain / loss must be reported on a Tax Return, even if there is no capital gain tax to pay. Before 2022-23, the old rule applied, based on a capital gain tax proceeds reporting limit of four times the annual exemption for the tax year.

Which people must complete a Self Assessment Tax Return?

According to the HMRC Self Assessment Manual the following people must complete a Tax Return if they are:

  • receiving income from self-employment or a partnership source (#)

  • receiving income from letting any property or land that exceeds £10,000 gross or if the net profit is more than £2,500 (*)

  • receiving income from savings and investments of £10,000 or more before tax

  • receiving income from dividends of £10,000 or more before tax

  • receiving untaxed income of £2,500 or more

  • receiving income in excess of £100,000 (including benefits) and has a live PAYE record

  • claiming for employment expenses in excess of £2,500

  • a CIS subcontractor and want to claim back their CIS payments

  • entitled to receive Child Benefit which is liable to the High Income Child Benefit Charge

  • making a claim for Enterprise Investment Scheme, Seed Enterprise Investment Scheme, Social Investment Tax Relief or Venture Capital Trust, where the relief claimed for each item is more than £10,000

  • receiving (or can be treated as receiving) income from a trust or settlement or any income from the estate of a deceased person and further tax is due on that income

  • receiving taxable foreign income, unless it is foreign dividend income covered by the £1,000 dividend nil rate band

  • in receipt of Capital Gain proceeds exceeding four times the annual capital gain tax annual exemption

  • due to pay Capital Gains Tax after deducting the annual exemption if they have not already paid Capital Gains Tax by completing a Capital Gains Real Time Transaction

The following would not usually have to register for Self Assessment

  • (#) Individuals who are eligible for the Trading Income Allowance and have turnover up to £1,000

  • (*) Individuals who are eligible for the Property Income Allowance and have rental income up to £1,000

Check if you need to send a Self Assessment Tax Return to HMRC

How long do I need to keep my Tax Return records?

You should keep the records that you have used to prepare your Tax Return for at least 12 months from the Tax Return filing deadline. The Tax Return filing deadline is the 31 January following the end of the tax year on 5 April. 

A non-business taxpayer preparing their Tax Return for 2023-24, i.e. the year ended 5 April 2024, should file their Tax Return before 31 January 2025. Their Tax Return records should be kept for a further 12 months to 31 January 2026 i.e. nearly two years from the end of the tax year.

If you are self-employed and your Tax Return includes details of your business profits, then you need to keep your records for at least 5 years after the Tax Return filing deadline.

A business taxpayer preparing their Tax Return for 2023-24, i.e. the year ended 5 April 2024, would file their Tax Return before 31 January 2025. Their Tax Return records should be kept for a further 5 years to 31 January 2030 i.e. nearly six years from the end of the tax year. If they do not prepare their business accounts to 31 March / 5 April each year, then they may have to keep their business records for longer. The Tax Return for 2023-24 will include any accounting period that ends in that tax year. Therefore, a person who prepares their annual accounts to say 31 May 2023, would will include those profits on their Tax Return for 2023-24, would need to keep their business records from 1 June 2022 until at least 31 January 2030.

If you send in your Tax Returns late, HMRC may subject it to a compliance check and the time limit for keeping your records may be extended. If you often miss Tax Return filing or payment deadlines, then this can increase the chance of receiving a tax investigation.

HMRC may wish to review your Tax Return and open a tax enquiry or investigation.  It is therefore a good idea to keep your Tax Return records for more than the minimum periods specified above. Find out more about HMRC fee protection insurance.

HMRC may ask for information about earlier tax years. They can request information about your taxes up to 20 years in cases of suspected deliberate tax evasion and fraud, up to 6 years if they consider you have not taken reasonable care when preparing your Tax Return and up to 4 years in cases of genuine innocent errors and mistakes.

You may be subject to a penalty for failure to keep records, even if your Tax Return is correct.

The Tax Return Form

To see exactly what must be included on a Tax Return, you should review the pages of the Tax Return directly and possibly read the helpful notes to the Tax Return published by HMRC.

HMRC has written to taxpayers who normally filed a paper Tax Return to tell them they will not receive a paper Tax Return for 2022/23 and future years. This is to encouraging them to complete and submit their Tax Returns electronically. However, the paper option is still possible on request. Taxpayers can request a paper Tax Return by telephoning HMRC on 0300 200 3610.

The SA100: Tax Return 

This is the main part of the Tax Return that all individuals must complete.

Use it to file your Tax Return for:

  • income and capital gains

  • student loan repayments

  • interest and dividends received

  • pensions and annuities received and pension contributions paid

  • taxable state benefits received

  • gift aid donations

  • child benefit repayable under the High Income Child Benefit Charge

  • claiming tax reliefs and allowances e.g. the marriage allowance


Supplementary pages

Supplementary pages must be used, where applicable, if the individual has received income from the following sources. 

Click and download the required supplementary pages for this and the previous three tax years.

SA101: Additional Information

SA102: Employment

SA103S: Self-employment (Short)

SA103F: Self-employment (Full)

SA104S: Partnership (Short)

SA104F: Partnership (Full)

SA105: UK Property

SA106: Foreign

SA107: Trusts etc

SA108: Capital Gains Summary

SA109: Residence, remittance basis

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