Complete Your Self Assessment with Confidence
Preparing your Self Assessment requires a clear picture of your income, relevant expenses and any additional information needed to explain your tax position. We help you bring these details together, complete your main return and supporting sections, and calculate the tax due based on your circumstances.
From employment and self-employment income to other sources that require disclosure, we review the information carefully and consider applicable reliefs and allowances. With clear explanations of your calculation and practical support throughout the filing process, we help you submit an accurate return, understand your payment responsibilities and plan ahead with confidence.
Forms
| Form | Description |
|---|---|
| SA100 | Main Self Assessment tax return for an individual |
| SA101 | Additional information for less common income, deductions and reliefs |
| SA102 | Employment |
| SA103 | Self-employment |
| SA104 | Partnership |
| SA105 | UK property |
| SA106 | Foreign |
| SA108 | Capital Gains Tax |
| SA109 | Residence and foreign income and gains |
| SA110 | Tax calculation summary for paper returns |
SA100 main return
- Purpose: lets HMRC calculate Income Tax, CGT and National Insurance, and covers student loans, Child Benefit charges and Marriage Allowance.
- Deadlines: paper by 31 October 2027, online by 31 January 2028 (or three months after the notice date if later). The balance and first payment on account are due 31 January 2028, and the second on 31 July 2028.
- Requirements: UTR, National Insurance number and income records. Register for Self Assessment by 5 October after the tax year ends.
SA101 additional information
Covers gilt interest, life insurance gains, share scheme income, redundancy payments above the exemption, foreign earnings, VCT and EIS relief, and annual payments. Same deadlines as the main return.
SA110 tax calculation summary
Lets a paper filer calculate their own liability. Paper returns received by 31 October 2027 can be calculated by HMRC, and online returns are calculated automatically.
Frequently Asked Questions
Let’s Discuss Your Requirements
Have a question about our services? Speak with our team to discuss your engagement, deadlines and the support you need.
Which Form Is the Main Self Assessment Return?
The main return is the SA100. HMRC uses it to calculate your Income Tax, Capital Gains Tax and National Insurance, and it also covers items such as student loans, the High Income Child Benefit Charge and Marriage Allowance. The SA100 also tells you which supplementary pages you need to complete, such as employment, self-employment, property or foreign income. We can work out which pages apply to you and prepare the whole return.
When Do I Need The SA101?
The SA101 is for less common income, deductions and reliefs that do not fit on the main return. Examples include gilt interest, life insurance gains, share scheme income, redundancy payments above the exemption, foreign earnings, VCT and EIS relief and annual payments. It follows the same deadlines as the main return. If you are unsure whether any of these apply, we can review your records and confirm.
Who Calculates The Tax On a Paper Return?
HMRC will calculate the tax for you if your paper return arrives by 31 October 2027. You can also work out your own liability using the SA110 tax calculation summary. Online returns are calculated automatically when you submit them, so you see the amount due straight away. Whichever method you use, it is worth checking the figures carefully before filing.
What are the Self Assessment Deadlines For 2026-27?
A paper return must be filed by 31 October 2027, and an online return by 31 January 2028 (or three months after the date of the notice to file, if that is later). The balance of tax and the first payment on account are due on 31 January 2028, and the second payment on account is due on 31 July 2028. Filing early gives you more time to plan for the payments.
What Do I Need to Complete a Self Assessment Return?
You will need your Unique Taxpayer Reference (UTR), your National Insurance number and records of all your income for the year. Depending on your situation, this may include your P60, P45 or P11D, self-employment records, rental income details, bank interest, dividends and details of any reliefs you are claiming. Collecting these early makes the return quicker to prepare and reduces mistakes.
When Must I Register For Self Assessment?
If you need to file a return for the first time, you must register for Self Assessment by 5 October after the end of the tax year in which you had the income. HMRC then issues your UTR, which is needed to file. Registering late can delay your return and may lead to penalties, so it is best to register as soon as you know you will need to file. We can handle the registration for you.
What Are Payments On Account?
Payments on account are advance payments towards your next year’s tax bill, normally made in two instalments. For 2026-27, the first payment is due on 31 January 2028 together with any balance for the year, and the second is due on 31 July 2028. They are usually based on your previous year’s tax liability. Knowing the dates in advance helps you plan your cash flow, and we can estimate the amounts for you.
Which Supplementary Pages Might I Need Alongside The SA100?
It depends on your income. The SA102 covers employment, the SA103 self-employment, the SA104 partnership income, the SA105 UK property, the SA106 foreign income, the SA108 Capital Gains Tax and the SA109 residence and foreign income and gains. The SA100 guides you to the pages that apply. We can review your circumstances and make sure every relevant page is completed and filed together.