Self Assessment 2025-26
Self Assessment tax return software: file your SA100 online
Taxley prepares your 2025-26 Self Assessment tax return (SA100), works out the tax with HMRC's published rules and files it to HMRC with your own Government Gateway login. It is built for employees and company directors with salary, dividends and interest, and covers one simple self-employment and one UK property business. The online deadline is 31 January 2027.
Price: £24.95 a return, every page Taxley covers included. No VAT added.
Last reviewed .
2025-26 Self Assessment: the key facts
- Tax year: 6 April 2025 to 5 April 2026.
- Online filing deadline: 31 January 2027 (paper returns: 31 October 2026).
- Pay the tax you owe by: 31 January 2027.
- New to Self Assessment? Register with HMRC by 5 October 2026 (GOV.UK: register for Self Assessment).
- Who Taxley's SA100 is for: UK residents in England, Wales or Northern Ireland with employment, director's pay, dividends, interest, pensions, one simple self-employment or one UK property business.
- How it files: through HMRC's Self Assessment online service, with your own Government Gateway user ID and password (GOV.UK: filing with commercial software).
Who is Taxley's Self Assessment software for?
Employees and company directors whose income is mainly salary, dividends and interest, plus people with one simple self-employment or one UK rental property. You must be UK resident and taxed in England, Wales or Northern Ireland, and you need a Government Gateway user ID to file.
A typical user is the director of a small limited company who pays themselves a salary and dividends and has some bank interest. The same Taxley account holds the company's Corporation Tax return and your own SA100. If you're still deciding how to pay yourself, see our guide to salary or dividends for a company director and the salary vs dividends calculator.
Whether you need a return at all depends on your income. HMRC's check if you need to send a Self Assessment tax return tool gives the answer, and if HMRC has sent you a notice to file, you must file even if you think you owe nothing.
What does Taxley's SA100 cover?
The main SA100 return and three supplementary pages: employment (SA102, up to 10 jobs, including company directors), short self-employment (SA103S, one business with turnover under £90,000) and UK property (SA105, one property business). The tax calculation follows HMRC's own published rules for 2025-26.
- Employment and directorships: pay, tax deducted, benefits and expenses from your P60 and P11D, and the director and close-company questions.
- Savings and dividends: UK interest and UK dividends.
- Pensions and benefits: the State Pension, other pensions, taxable state benefits and other taxable income.
- Reliefs: personal pension contributions and Gift Aid donations.
- Charges: student and postgraduate loan repayments (plans 1, 2 and 4 and postgraduate loans) and the High Income Child Benefit Charge, unless your partner had the higher income for only part of the year.
- Self-employment (short pages): income and allowable expenses, the trading allowance, capital allowances and Class 4 National Insurance.
- UK property: rents and expenses, the property allowance, residential finance costs and replacement of domestic items.
- Tax already paid: tax collected through your tax code, and the bank account for any repayment.
How does Taxley compare with HMRC's online service and an accountant?
All three end with the same return at HMRC, and in every case you stay responsible for what it says. HMRC's own service is free; an accountant or tax adviser prepares and files it for you for a fee; Taxley sits in between, with the return prepared by you and checked by software before it is sent.
| Taxley | HMRC's online service | An accountant or tax adviser | |
|---|---|---|---|
| Who prepares it | You, by answering plain questions and entering your figures. | You, in HMRC's online return. | The adviser, from your records. |
| What it covers | The SA100 with employment, short self-employment and UK property pages (see the limits below). | The SA100 and most pages, but not some returns, such as those of non-residents, Lloyd's underwriters or ministers of religion. | Whatever you agree with the adviser. |
| The tax calculation | Shown on the review page once you save your figures, using HMRC's published 2025-26 rules. | Shown by HMRC before you submit. | Prepared by the adviser. |
| Who submits it | You, through Taxley, with your Government Gateway login. | You, signed in to your HMRC online account. | The adviser, as your agent. |
| Cost | £24.95 per return, paid when you file. | Free. | Set by the firm; ask for a fixed quote. |
| Advice | No personal advice. | HMRC guidance and helplines. | Yes, tailored to you. |
How do you file a Self Assessment return with Taxley?
In five steps: answer a few questions, enter your income, check the tax, review the return and file it with HMRC using your Government Gateway login. You see every page of the return and the tax calculation before anything is sent.
1. Answer a few questions
Tell Taxley what kinds of income you had. If your return needs something Taxley doesn't cover, it says so straight away; your return is saved and you aren't charged.
2. Enter your details and income
Add your UTR and personal details, then the figures from your P60 and P11D, dividends, interest, pensions, Gift Aid and any self-employment or property income.
3. Check the tax calculation
See the tax worked out with HMRC's published 2025-26 rules, including student loan repayments, the High Income Child Benefit Charge and Class 4 National Insurance.
4. Review the return
Taxley checks the return against HMRC's own schema and business rules and shows you every page before you send it. Make the declaration.
5. File with HMRC
Pay, then enter your Government Gateway user ID and password. Taxley sends the return through HMRC's Self Assessment online service and shows HMRC's reply on your return.
Taxley uses your Government Gateway password only to send the return and never saves it to your account or the return (it is held encrypted while sending; if sending fails, it is deleted within three days); your user ID is kept, encrypted, with the submission record. If HMRC rejects the return, Taxley shows the reason so you can correct it and send it again.
When is the 2025-26 Self Assessment return due?
By 31 January 2027 if you file online, which is also the date to pay any tax you owe. The paper deadline is 31 October 2026. If you pay through your tax code and owe less than £3,000, filing online by 30 December 2026 lets HMRC collect it through your 2027-28 tax code instead (GOV.UK: Self Assessment deadlines).
A late return costs £100 straight away, even if you owe no tax. After 3 months HMRC adds £10 a day for up to 90 days, and after 6 and again after 12 months a further 5% of the tax due or £300, whichever is more. Paying late adds interest and late payment penalties (GOV.UK: Self Assessment penalties). If you make payments on account, the second one towards the next year is due by 31 July 2027 (GOV.UK: payments on account).
What doesn't Taxley's Self Assessment cover?
Anything outside the income listed above, including Scottish taxpayers, capital gains, foreign income and partnership income. Taxley asks about these at the start, so you know before you enter any figures. If your return needs one of them, use other commercial software, an adviser, or HMRC's online service where it can be used. Taxley doesn't cover:
- Scottish taxpayers, people who weren't UK resident, split-year treatment or the overseas pages;
- foreign income or gains, capital gains, or partnership income (SA104);
- more than one self-employment, the full self-employment pages, turnover of £90,000 or more, a trading loss or voluntary Class 2 National Insurance;
- a UK property loss, Rent a Room relief, furnished holiday lettings, lease premiums or capital allowances on property;
- income from trusts, settlements or estates; ministers of religion or Lloyd's underwriters;
- pension savings tax charges or lump sums, redundancy and other lump sums, share schemes or life insurance gains;
- VCT, EIS or SEIS relief, maintenance payments, qualifying loan interest or losses set against other income;
- Marriage Allowance, Married Couple's Allowance or Blind Person's Allowance;
- the High Income Child Benefit Charge where your partner had the higher income for only part of the year;
- payments on account (HMRC sets them from your return) or amending a return you've already sent.
Frequently asked questions
When is the 2025-26 Self Assessment deadline?
The online return for the 2025-26 tax year is due by 31 January 2027, and any tax you owe must be paid by the same date. The paper deadline is 31 October 2026. If HMRC sent your notice to file after 31 October 2026, you have 3 months from the date of the notice instead.
Can I file my Self Assessment return free with HMRC?
Yes. HMRC's own online service is free to use for most people. Taxley is commercial software: it asks plain questions, works out the tax from your figures with HMRC's published rules, checks the return against HMRC's rules before it is sent, and files it with your Government Gateway login.
Do company directors have to file a Self Assessment return?
Being a director isn't, on its own, one of the reasons GOV.UK lists for filing. You must file if HMRC sends you a notice to, and income that isn't taxed at source, such as dividends or savings interest, may mean you need a return. HMRC's online checker gives the answer for your year.
What do I need before I start?
Your 10-digit Unique Taxpayer Reference (UTR), your Government Gateway user ID and password, and the year's figures: your P60 and any P11D from each job, dividend and interest totals, pension contributions and Gift Aid, and any self-employment or property income and expenses.
Does Taxley work out my payments on account?
No. Taxley works out the tax on your return, including any student loan repayment, High Income Child Benefit Charge and Class 4 National Insurance. It doesn't calculate payments on account for the next year or a claim to reduce them; HMRC sets those from your return.
Can I use Taxley if I sign in to HMRC with GOV.UK One Login?
Software such as Taxley connects to HMRC with a Government Gateway user ID and password. If you sign in to Self Assessment with GOV.UK One Login, GOV.UK says to create a separate Government Gateway user ID and password to use with your software.
How much does Taxley charge to file a Self Assessment return?
£24.95 per return, with every page Taxley covers included and no VAT added. You can prepare and check the whole return first, and pay when you file. If HMRC rejects the return, you can correct it and send it again at no extra charge.
Related pages
File your 2025-26 return before 31 January 2027
Answer a few questions, check the tax, and file it to HMRC with your Government Gateway login.