Preparing for your first tax return

Your first tax return is easier to prepare when income statements, business records and existing tax deductions are organised before you start the form. Establish which supplementary sections apply and obtain access to the correct HMRC service in good time.

Build a missing-information list with owners and dates. Keep estimates clearly marked for discussion; do not substitute a bank balance for the income earned during the year.

Build the return around a source inventory

Start with the tax year and list every place from which money or a taxable benefit may have arisen. Include employment that ended early in the year, freelance work, pensions, property, savings and investments where relevant. Mark each source as confirmed, awaiting evidence or needing a tax assessment. This gives the preparer an overview before individual documents begin arriving through different channels.

HMRC's Self Assessment guidance explains the reporting framework and supplementary information that may be required. ^[1] Use the actual circumstances to identify the relevant sections. Do not copy a friend's completed return or assume that the main form covers every source. A first-time filer who worked overseas or sold an asset may need additional analysis even if their new business is straightforward.

Separate gross figures from amounts received

For employment, gather the P60 or P45 and relevant benefits information. For business activity, reconcile invoices, cash takings and platform records to bank receipts. Note deductions such as processor charges rather than treating a net settlement as the whole sale. Keep movements of personal savings and borrowed money distinguishable from income so the preparer does not have to infer their nature from short bank descriptions.

Arrange records in source folders with a concise index. A document name should identify what it is and which period it covers, without exposing unnecessary personal details in a public file name. Keep a query sheet for missing evidence and avoid sending repeated versions of the same spreadsheet without an explanation. The latest schedule should show what changed and which figures remain provisional.

Explain expenses before selecting tax treatment

A new sole trader often has purchases made before the first customer payment, mixed personal and business spending, and equipment that will be used over several years. Describe these facts and retain the supporting documents. The accounting method and specific tax rules affect treatment; a business card payment alone does not establish that the entire amount is deductible in the current return.

Use Allowable expense evidence for sole traders to organise expense evidence and Cash basis and traditional accounting to discuss the accounting method. Ask the accountant which decisions require further information rather than entering every purchase into the same category. Where an allocation is proposed, explain how it reflects actual use. An unsupported percentage can make a spreadsheet look complete while leaving the important factual question unanswered.

Review the calculation before authorising filing

Compare the draft return with the source inventory. Check personal details, income totals, tax deducted and reliefs. Ask for an explanation of material differences from your own expectation, including a balance due despite PAYE deductions or an unexpected refund. The purpose of review is to understand the calculation sufficiently to approve accurate information, not merely to confirm that the software has produced a final page.

Keep the approved version and the preparer's answers together. If another document arrives before submission, identify the affected figures and obtain an updated calculation where needed. Do not approve an old draft while assuming that a later attachment will automatically be incorporated. Confirm how the actual filing acknowledgement will be supplied and who investigates a rejected or incomplete submission.

Plan the first payment as a separate task

Ask whether payments on account arise and how they affect the amount payable alongside the balancing liability. ^[2] The first payment can surprise someone who budgeted only for the tax shown for the completed year. Use Payments on account: planning cash flow to prepare a realistic cash forecast and keep future estimates distinct from the final calculation for the year being filed.

For Self Assessment tax return support, send the source inventory, organised evidence and a focused list of uncertainties. Agree the scope, approval timetable and payment responsibilities early. Keep access credentials private and use the proper agent authorisation process. After filing, retain the return, calculation and acceptance evidence in a place you can access independently of the preparer's account. This gives the next year's preparation a reliable starting point and makes an adviser change much easier to manage. Keep a separate list of questions answered during preparation, including the evidence used, so the same uncertainty does not have to be investigated again next year.

Illustrative scenario

A new consultant has employment income for part of the year and then self-employment receipts. Their preparation pack separates the P45, business transactions and pension contributions so none is counted twice.

Preparation checklist

• Confirm online access
• Gather employment statements
• Reconcile business receipts
• List unresolved questions