Prepare for your first Self Assessment tax return

Your first Self Assessment return can feel daunting, but most of the work is gathering the right information in advance. This guide helps you prepare your figures and documents so the return itself is straightforward. It is general information only, so check HMRC guidance on GOV.UK or speak to an accountant if your situation is complex.

Step by step

1. Check your registration and login

   Make sure you have registered for Self Assessment and received your Unique Taxpayer Reference. Check you can sign in to your Government Gateway account well before the deadline. If you have lost access, start the recovery process early, as it can take time.

2. Confirm the tax year and your dates

   The return covers the tax year from 6 April to 5 April. Note your start date if you began trading during the year. The online return and any tax owed are normally due by 31 January after the end of the tax year.

3. Total your income

   Add up all your self-employed income for the tax year from your invoices, bank statements and payment records. Also gather details of other income you need to report, such as employment income from your P60, interest or rental income. Check that nothing has been missed or counted twice.

4. Total your allowable expenses

   Group your business expenses into categories such as materials, travel, phone, insurance and professional fees. Only include the business part of any cost that is also used personally. Keep the receipts and records that support each figure.

5. Estimate the tax and plan payment

   Use HMRC's guidance or your software to estimate your tax and National Insurance. Check whether payments on account will apply, as your first bill can include part of next year's tax. Compare the estimate with the money you have set aside.

6. Complete and submit the return

   Fill in the return carefully, check every figure against your records and submit it before the deadline. Save a copy and the submission confirmation. Pay the tax due by the deadline using an official HMRC payment method.

Ready-to-use checklist

• UTR and Government Gateway login confirmed
• Tax year dates and trading start date noted
• Self-employed income totalled from records
• Other income details gathered
• Expenses grouped and supported by receipts
• Tax estimate compared with savings
• Return submitted and confirmation saved
• Payment made by the deadline

Practical tips

• File early in the autumn so you know the bill well before January.
• If you cannot pay in full, contact HMRC before the deadline about a payment plan.
• Only use official HMRC services; ignore messages offering tax refunds by text or email.

Common problems