Yes. You can prepare and file your own Self Assessment tax return. HMRC’s online service is suitable for many straightforward cases. You remain responsible for complete income, correct claims, filing on time and paying the bill.
Before starting
- check that a return is required;
- register and obtain or reactivate the UTR;
- create or access the Government Gateway account;
- collect records for every income source and claim;
- allow time before the 31 January deadline.
What HMRC’s online service can cover
It supports common employment, self-employment, UK property, savings, dividends, pension and capital-gains entries. Some complex returns, non-resident cases, trusts and specialised supplementary pages may require commercial software or paper forms.
Step-by-step filing process
- Sign in through GOV.UK.
- Confirm personal details and residence questions.
- Select every section that applies.
- Enter employment and pension data from P60, P45 and P11D records.
- Enter self-employment income, expenses and capital allowances.
- Add property, savings, dividends, foreign income and gains.
- Claim pension, Gift Aid and other reliefs.
- Review student loan, Child Benefit and payments on account.
- Check the calculation and compare it with expectations.
- Submit, save the receipt and arrange payment.
Records you need
- UTR and National Insurance number;
- P60, P45, P11D and pension statements;
- sales and expense records;
- rent and property-cost schedules;
- bank interest and dividend reports;
- investment and crypto disposal records;
- foreign income and tax evidence;
- pension and Gift Aid certificates;
- CIS deductions and student-loan information.
Common DIY mistakes
- reporting net platform receipts instead of gross income and fees;
- claiming private or capital costs as expenses;
- forgetting payments on account;
- omitting foreign income or bank interest;
- claiming both trading allowance and actual expenses;
- using the wrong mileage or home-working rate;
- failing to report a property disposal within 60 days;
- assuming pre-populated HMRC data is complete;
- submitting without saving a copy.
How to check the calculation
Compare taxable income with source totals, confirm the Personal Allowance and tax bands, reconcile PAYE and CIS credits, review Class 4 National Insurance and check whether payments on account are included. Unexpected refunds or bills should be investigated before submission.
Provisional figures
Where records genuinely cannot be finalised, tax rules can permit provisional figures identified as such. Replace them promptly through an amendment. Do not use estimates simply to avoid gathering available records.
Deadlines
| Action | Normal deadline |
|---|---|
| Register | 5 October |
| Paper return | 31 October |
| Online return and balancing payment | 31 January |
| Second payment on account | 31 July |
Amending a return
You can normally amend within 12 months of the filing deadline. Keep the original and amended calculation. After the window, an overpayment-relief claim or disclosure may be required.
When to obtain help
- non-UK residence or foreign-income regimes;
- large capital gains or crypto histories;
- multiple trades, partnerships or property portfolios;
- complex pension charges or loss relief;
- incorporation, cessation or basis changes;
- HMRC enquiries or deliberate omissions;
- records that do not reconcile.
Software alternatives
Commercial software can import bookkeeping data, handle unsupported supplementary pages and provide extra checks. Confirm HMRC recognition, data security, pricing and export access. Software does not decide whether a tax treatment is legally correct.
Making Tax Digital
In-scope sole traders and landlords must use compatible software from April 2026 above £50,000 qualifying income, April 2027 above £30,000 and April 2028 above £20,000. Quarterly updates do not replace the year-end declaration.
After filing
- save the PDF or full return, calculation and receipt;
- pay using the correct UTR reference;
- note payments on account;
- retain records for the statutory period;
- check the HMRC online balance;
- amend errors promptly.
Related: when an accountant may help.
Official guidance
This guide is general information. Obtain advice where the return contains complex or uncertain treatment.
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