Self Assessment · Tax Returns · Chelmsford
Self Assessment tax returns, done right and on time
Tax-Pert Accountants prepare and file your Self Assessment tax return for you. Our chartered certified accountants in Chelmsford help you claim every allowance and relief you are entitled to, and make sure you never miss a deadline.
Key Self Assessment dates
2025-26 tax year: 6 April 2025 to 5 April 2026. The 31 October 2026 paper deadline has passed.
31 Jan
online filing and payment deadline for the 2025-26 tax year
£100
penalty as soon as your return is late
£1,000
self-employed income, before expenses, above which you must file
5 Oct
deadline to tell HMRC you need to file for the first time
Who needs one
Do you need to file a Self Assessment tax return?
You usually do if any of these applied in the last tax year. Not sure? Ask us and we will tell you.
Sole traders
You were self-employed and earned more than £1,000, before deducting expenses.
Landlords
You rent out property. Depending on the amounts involved, you may need to file.
Business partners
You were a partner in a business partnership.
Investors and sellers
You paid Capital Gains Tax when you sold something that rose in value.
Child Benefit charge
You owe the High Income Child Benefit Charge and do not pay it through PAYE.
Overseas or untaxed income
You have income from abroad, or other income that has not been taxed at source.
Key dates
Self Assessment deadlines and payments
Mark these in your diary, or leave it to us and we will remind you.
| Deadline | What you need to do | Tax year |
|---|---|---|
| 30 December 2026 | Send your online return if you want any tax owed collected through your tax code (if you qualify) | 2025-26 |
| 31 January 2027 | File your online Self Assessment tax return | 2025-26 |
| 31 January 2027 | Pay your tax bill, and make your first payment on account if one is due | 2025-26 |
| 31 July 2027 | Make your second payment on account, if one is due | 2026-27 |
| 5 October 2027 | Tell HMRC you need to file, if you are new to Self Assessment | 2026-27 |
Registering late
If you register after 5 October, HMRC sets a return deadline of three months from its letter or email. Your tax is still due by 31 January.
Payments on account
Many self-employed people and landlords pay tax in two advance instalments, on 31 January and 31 July. We work out what you owe and when.
Paying through your tax code
If you are employed and owe a small amount, filing online by 30 December may let HMRC collect it through your tax code.
What is included
Everything handled, start to finish
We take care of your tax return from the first question to the final confirmation from HMRC.
Your Self Assessment service includes
- Checking whether you need to file, and which income to report
- Gathering and checking your income and expense records
- Claiming the allowances, reliefs and expenses you are entitled to
- Preparing your return and calculating your tax bill
- Explaining what you owe, when to pay and any payments on account
- Filing online with HMRC and sending you confirmation
- Dealing with HMRC on your behalf about your return
Instant quote
Your fixed fee, agreed upfront
Tell us a little about your income and see your personalised fee in about two minutes. No obligation and no surprises later.
How it works
From documents to filed in four steps
No jargon and no chasing. You tell us about your income and we do the rest.
01
Get a quote
Answer a few questions and see your fee straight away.
02
Send your details
Send us your income and expense records.
03
We prepare and check
We complete your return, calculate your tax and explain the figures.
04
Approve and file
You approve it, we file with HMRC and confirm it is done.
Get ready
What to have ready
Gather these and the process is quick. Missing something? We will help you track it down.
Penalties
What happens if you file or pay late
The penalties add up quickly, but they are easy to avoid.
Late filing
£100 as soon as your return is late. After three months, £10 a day for up to 90 days, which is £900 at most.
Six and twelve months late
A further penalty at each point: 5% of the tax due or £300, whichever is higher.
Late payment
5% of the unpaid tax at 30 days, six months and twelve months, plus interest on what you owe.
Why Tax-Pert
Chartered Certified Accountants in Chelmsford
Straightforward advice, a clear fee and a local team who know your business.
Registered HMRC tax agent
We can file and deal with HMRC on your behalf.
Plain-English advice
We explain your figures so you understand your bill.
Fixed fee
Know your cost upfront. No hourly-rate surprises.
Local Chelmsford team
Real people you can call, email or meet.
FAQs
Questions about Self Assessment
Straight answers in plain English.
Do I need to file a Self Assessment tax return?
You usually do if you were self-employed and earned more than £1,000 before expenses, were a partner in a business partnership, had to pay Capital Gains Tax, or owe the High Income Child Benefit Charge. Other situations apply too, such as rental or untaxed income. Tell us about your income and we will confirm.
What is the Self Assessment deadline?
For the 2025-26 tax year, your online return and any tax you owe must reach HMRC by 11:59pm on 31 January 2027. The paper return deadline was 31 October 2026. If you register late, HMRC sets a deadline of three months from the date of its letter or email.
What happens if I miss the deadline?
You get a £100 penalty as soon as your return is late. After three months, it adds £10 a day for up to 90 days (£900 at most). At six and twelve months there is a further penalty each time of 5% of the tax due or £300, whichever is higher. Late payment is charged separately, plus interest.
I have a job and a side income. Do I need to file?
Possibly. If your self-employed income was more than £1,000 before expenses, you must register and file. Other income, such as rent or investments, may also need reporting. Ask us and we will tell you for certain.
What are payments on account?
They are advance payments towards your next tax bill, made in two instalments on 31 January and 31 July. Not everyone has to make them. We work out whether they apply to you and how much to pay.
Can you help if I am already late or have missed years?
Yes. We can prepare and file overdue returns and deal with HMRC on your behalf. Penalties build up over time, so it is best not to wait.
How much does it cost?
Your fee depends on your income and how complicated your tax affairs are. Use our Get a Quote tool for a personalised fee in about two minutes.
Will Making Tax Digital change my Self Assessment?
If your qualifying income was over £50,000 in 2024-25, MTD for Income Tax has applied since 6 April 2026. The threshold drops to £30,000 in April 2027 and £20,000 in April 2028. You then send quarterly updates and a final declaration instead of a tax return. Use our Check If MTD Affects You tool to find out where you stand.
Ready to get your tax return sorted?
Get your quote in two minutes, or call us and talk it through.