Self Assessment is the system HMRC uses to collect Income Tax from peoplewhose tax is not automatically deducted at source. You declare your income,claim allowable expenses, and calculate the tax you owe for that tax year and then pay by the 31st January deadline.
If you earn money outside of PAYE, whether from self-employment, rental property, dividends, investments, or overseas income, HMRC expects you to file a self assessment tax return each year.
Key points at a glance:
- Self Assessment is used to report untaxed income.
- You work out your own tax bill, based on your actual earnings.
- Never filed before? You need to register for self assessment by 5 October.
- The deadline for online filing is 31 January after the end of the tax year.
- If you miss the deadline, there’s a £100 penalty, even if you don’t owe any tax.
Who must file a Self Assessment Tax Return?
You must file a Self Assessment Tax Return if any of thefollowing apply to you during the 2025/26 tax year:
- You are self-employed or a sole trader earning more than £1,000
- You are a company director receiving salary, dividends, or benefits in kind
- You earn over £100,000 per year from any source
- You receive rental income from a property you let out
- You have capital gains from selling shares, property, or other assets
- You earn income from cryptocurrency trading or staking
- You receive dividends above the tax-free allowance of £500
- You have income from abroad or work as a non-domiciled UK resident
- You receive Child Benefit and your household income exceeds £60,000
- HMRC has specifically asked you to file a return
Key Self Assessment Deadlines for 2025/26
|
Deadline
|
What You Need to Do
|
|
5th October 2025
|
Register for Self Assessment with HMRC if you are new to it this year
|
|
31st October 2025
|
Deadline for filing a paper Self Assessment Tax Return
|
|
31st January 2026
|
Deadline to file online and pay any tax owed for 2024/25 tax year
|
|
31st July 2026
|
Second Payment on Account due for the 2025/26 tax year
|
What happens if you miss the deadline?
If you miss the 31 January deadline, HMRC will automatically issue a £100 penalty. After three months, daily penalties of £10 apply (up to £900). Six and twelve months late brings further charges. Interest is also charged on any overdue amounts.
Who Needs to File Self Assessment Tax Returns?
Self Assessment isn’t identical for everyone. Different taxpayers face different risks. Filing incorrectly can mean penalties, interest, or overpaying tax. Here’s who typically needs to file and how GoForma can help you stay organised.
- Self-Employed & Sole Traders
- Limited Company Directors
- Contractors (Inside & Outside IR35)
- Landlords
- High Earners Over £100k
- Individuals with Dividend or Investment Income
- Crypto Investors
- CIS Subcontractors
What’s Included in GoForma's Self Assessment Tax Return Service?
GoForma's Self Assessment Tax Return service covers everything from initial HMRC registration through to final filing and post-submission support, all handled by your named, qualified accountant for a single fixed fee.
Here is exactly what is included.
- HMRC Self Assessment registration (if you are not yet registered)
- Government Gateway setup and HMRC agent authorisation
- Full income review across all sources: employment, self-employment, dividends, property, capital gains, and crypto
- Expense review and optimisation to identify all legitimate claims
- Dividend and salary tax calculations for company directors
- Capital Gains Tax reporting for shares, property, and other assets
- CIS tax reclaim calculations for subcontractors
- Property income reporting under current HMRC rules
- Cryptocurrency disposal and gains reporting
- Payment on Account calculations to help you plan for the July deadline
- HMRC authorisation and direct filing on your behalf
- Post-filing tax liability summary in plain English
- Payment deadline reminders for 31 January and 31 July
What is NOT Included (So There are No Surprises)
Our standard service does not include ongoing monthly bookkeeping, VAT returns, Corporation Tax filings, or payroll. If you need any of these, you can upgrade to a monthly accounting package at any time. We will always tell you upfront if your return is more complex than a standard filing and requires a bespoke quote.
Do You Need an Accountant for Self Assessment, or Can You File Yourself?
You can legally file your own Self Assessment Tax Return using HMRC's free online portal. Millions of people do it every year. But whether you should depends on the complexity of your income and how confident you are with HMRC's rules.
|
Factor
|
Filing Yourself (via HMRC)
|
Using GoForma
|
|
Cost
|
Free
|
From £195 + VAT
|
|
Time required
|
3–10+ hours depending on complexity
|
Under 30 minutes from you
|
|
Risk of errors
|
Higher - easy to miss expenses or miscalculate
|
Low - ACCA/AAT accountant reviews everything
|
|
Expense optimisation
|
Only what you know to claim
|
Proactive review of all allowable deductions
|
|
HMRC queries
|
You handle all correspondence
|
We handle it as your authorised agent
|
|
Complex income
|
Can be very difficult to get right
|
Fully supported: dividends, crypto, CGT, CIS
|
For a simple return with one job, one income source, no investments, filing yourself is entirely reasonable. But if you are a director, landlord, contractor, or you have multiple income types, a professional review typically saves you more in tax than the service costs. Our accountants regularly identify overlooked expenses and miscalculated allowances that more than cover the fee.
Making Tax Digital for Income Tax (MTD for ITSA) — What it Means for Your Self Assessment
Making Tax Digital for Income Tax Self Assessment (MTD for ITSA) is a significant change from HMRC that will affect how self-employed individuals and landlords file their tax returns. From April 2026, those earning over £50,000 from self-employment or property will be required to use HMRC-approved software to keep digital records and submit quarterly updates.
Does this Affect You?
If you are self-employed or receive rental income above these threshold, yes, and you need to be prepared. GoForma is already MTD-ready and operates HMRC-compatible software (FreeAgent, Xero) for all clients. If you are a new client filing your Self Assessment for 2024/25 or 2025/26, we can set you up with the right tools and workflow now, so the MTD transition is seamless.
Speak to one of our accountants about your MTD obligations and how you can transition smoothly to the new system using our MTD for Income Tax service.
Ready to File Your Self Assessment Tax Return?
Stop putting it off. The 31st January deadline does not change, and HMRC's penalties start the moment you miss it. GoForma's Self Assessment Tax Return service is designed for people who want it done right, done on time, and done without drama.
At GoForma, our qualified UK accountants handle your Self Assessment from preparation to submission. We review your income, apply the correct tax rules, and calculate exactly what you owe.
Book a free 20-minute consultation with one of our ACCA or AAT-qualified accountants. We will clarify your filing requirements, give you an honest assessment of your tax position before you commit to anything.
Take control of your taxes today and file with confidence.
.avif)
.png)