Self-Employment Tax: Register to Submit / Lesson 9 of 12
Filling in the return, section by section
The form is long. The part that applies to you usually is not.
The short answer
- ✓ Answering the tailoring questions honestly hides most of the form
- ✓ You submit totals, not your accounts or receipts
- ✓ Read the tax calculation before submitting: payments on account appear there
- ✓ You can amend a submitted return for 12 months after the filing deadline
Why the form looks so big
The Self Assessment return covers every kind of taxpayer there is: landlords, company directors, people with foreign income, trustees, partners. The online version starts by asking which of those apply to you, and then hides everything else. Answer that first section honestly and the form shrinks dramatically.
The shape of it
| Section | What it wants | Where your answer comes from |
|---|---|---|
| Tailor your return | Which income types apply to you | Your own situation |
| Self-employment | Turnover, expenses, profit | Module 2 of this course |
| Employment | Pay and tax deducted | Your P60 or P45 |
| Other income | Interest, dividends, property | Bank and platform statements |
| Tax reliefs | Pension contributions, Gift Aid | Your own records |
| Check and submit | Confirms the calculation | HMRC works it out for you |
The self-employment pages
This is the part that matters here. If your turnover is below the VAT threshold you can complete the short version, which asks for very little.
Business name and description
Accounting period start and end dates
Total turnover
Total allowable expenses (one figure, or itemised if you prefer)
Any capital allowances
Net profit or loss (calculated for you)You are not required to submit your accounts, your receipts or your spreadsheet. You submit the totals. The records exist so that you can prove those totals if you are ever asked, which is a different thing entirely.
Itemised or a single figure?
Below the VAT threshold you may enter one combined expenses figure rather than breaking it into categories. Many people still itemise, and there is a decent argument for it: a return showing sensible category splits looks like the output of a real bookkeeping system, and a single round number does not.
The bit HMRC does not spell out
The calculation HMRC shows you before you submit is worth actually reading. It is the clearest statement you will get of how your bill was arrived at, broken into income tax and each class of National Insurance, and it will show any payments on account being added. People click past it in a hurry to be finished, then get a surprise in January that was displayed on screen weeks earlier.
Second: you can amend a submitted return for 12 months after the filing deadline. A rushed submission is not final. If you file in a panic on 31 January and then find a folder of receipts in February, you can correct it. Filing something reasonable on time and amending later is nearly always better than filing late.
Before you press submit
- Check the figures against your records one final time, especially turnover
- Read the tax calculation summary, including any payments on account
- Save or print the submission receipt, which carries your submission reference
- Note the payment deadline, which is the same day as the filing deadline
Common mistakes
- Skipping the tailoring questions. Answer them properly and most of the form disappears.
- Not reading the calculation. It is where the January surprise is announced in advance.
- Assuming filing means paying. They are two separate acts on the same deadline.
- Believing a filed return cannot be corrected. You have 12 months after the deadline to amend.
Try it on your own numbers
This is the same calculator as the full tool page, using 2026/27 rates.
About you and your income
Tell us where you live and how you earned money - we only ask about the sources you tick.
Which of these did you have in the tax year? (tick all that apply)
Your income for the year
Use your P60/P45, business records, dividend vouchers and bank statements. Whole-year totals, before tax.
Employment (PAYE)
Self-employment
UK property
Dividends
Savings interest
Capital gains
The first of gains is exempt. We apply in your basic-rate room and above it.
Expenses, allowances & reliefs
These reduce your bill - don't skip them. Not sure what you can claim? Run the expenses checker first.
Self-employment expenses
Best when your real expenses are under £1,000. You can't claim both.
Property expenses
Estimated bill so far
Total liability minus already collected at source. Calculated with 2026/27 rates.
This is an estimate and organiser, not tax advice, and nothing is sent to HMRC - confirm every figure on GOV.UK before you file.
- Total income
- Personal Allowance (tapered - income over £100k)
- Income Tax
- Class 4 National Insurance
- High Income Child Benefit Charge
- Student loan due via Self Assessment
- Capital Gains Tax
- Total liability
- Less PAYE / CIS already paid
Your profit is under the £ small profits threshold - you can pay voluntary Class 2 NI (£/week) to protect your State Pension record. Not added to this bill.
When you'd pay (31 January after the tax year ends, then 31 July)
- 31 January - balancing payment
- 31 January - 1st payment on account
- 31 July - 2nd payment on account
- Total due on 31 January
What goes where on your return
| Form / section | What to enter | Your figure |
|---|---|---|
Box numbers follow the current SA forms and can move slightly year to year - always match the description printed on the form or online screen you're completing.
Saved scenarios
| Scenario | Liability | Balance due | |
|---|---|---|---|
Key takeaways
- ✓ Answering the tailoring questions honestly hides most of the form
- ✓ You submit totals, not your accounts or receipts
- ✓ Read the tax calculation before submitting: payments on account appear there
- ✓ You can amend a submitted return for 12 months after the filing deadline
Check you have got it
3 quick questions. No score is kept, and you can change your mind.
1. Do you have to send HMRC your receipts and accounts with the return?
2. You filed in a rush and later realise you missed some expenses. What can you do?
3. Filing your return on 31 January also pays the bill.
Sources
Finished this lesson?
Mark it done and we will remember where you got to.
You are 9 lessons in. Want to keep your progress?
Right now your place is saved in this browser only. A free account keeps it across devices, unlocks the end-of-course exam and certificate, and gives you a personal action plan at the end. No card, no upsell.
