We prepare and file Self Assessment tax returns for people in Cardiff, as your registered HMRC agent, for a fixed fee agreed before any work starts. The return for the 2025 to 2026 tax year has to be filed and paid by 11:59pm on 31 January 2027.
Most people in Cardiff who come to us in October are not late. They are tired of the January version of this, where the records are somewhere, the HMRC login is somewhere else, and the figure that comes out at the end is the first time anyone has seen it. Starting now changes the order: you find out what you owe while there is still time to do something about it.
There is also one thing about filing from Cardiff that nobody mentions until it goes wrong, and it is worth getting straight before anything else.
What does a Self Assessment accountant in Cardiff do?
- A fixed fee, quoted on the call, before any work begins.
- Agent authorisation with HMRC, so we can see what they already hold on you.
- The residence flag and tax code prefix checked against where you actually lived.
- The return prepared, reviewed with you, and filed once you have signed it off.
- Payments on account worked out, with a view on whether reducing them is worth the interest risk.
- HMRC correspondence afterwards, coming to us rather than to you.
Fifteen minutes is enough to tell you what your return involves and what it will cost. No obligation, and no sales pitch at the end of it.
Or call 029 2002 6505
Do people in Cardiff pay a different rate of Income Tax?
Live in Cardiff and HMRC treats you as a Welsh taxpayer. It marks that with a C at the front of your tax code and applies the Welsh rates of Income Tax to your employment income, your self employment profit and your rental profit.
For 2026 to 2027 those rates are the same as England and Northern Ireland: nothing up to the £12,570 personal allowance, 20 per cent to £50,270, 40 per cent to £125,140 and 45 per cent above that. Dividends and savings interest are taxed at the UK rates either way. So being Welsh does not raise your bill.
What it raises is the chance of a mismatch, because the flag sits on HMRC’s record rather than on your return, and it only updates when HMRC knows you moved. Cardiff is half an hour from the English border. People work in Bristol and live in Pontcanna, keep a flat in Newport, or move across the Severn mid year. HMRC decides Welsh taxpayer status on where your main home was for most of the tax year, 6 April to 5 April, not on where you were on 5 April and not on where the work is. We check that first, before we touch a number.
Four Self Assessment dates for the 2025 to 2026 tax return
Only one of them is 31 January, and only one of them involves paying anything
Register with HMRC if you have never filed before. This date has passed, so register now and HMRC sets your deadline three months from the date on its letter.
Paper return deadline, 11:59pm. Almost nobody needs this one, but missing it removes the paper option entirely.
File online by 11:59pm to ask for the tax to be collected through your PAYE code across the following year instead of paid in one go.
Online return, the balancing payment for 2025 to 2026, and the first payment on account for 2026 to 2027. All three, 11:59pm.
The one people miss. 31 January carries three separate charges on the same day, not one. The second payment on account then follows on 31 July 2027.
Who has to file a Self Assessment tax return in Cardiff?
The Cardiff list has not changed much in a decade, and it is mostly people whose tax got complicated by accident rather than by design.
- Sole traders and freelancers whose gross trading income went over £1,000 and who now have to file whether they made a profit or not.
- Landlords with one or two properties, where the finance cost restriction and the allowable expenses do most of the damage.
- Company directors taking a salary and dividends, where the dividend rates moved to 10.75 and 35.75 per cent from 6 April 2026.
- Higher earners losing the personal allowance above £100,000, or caught by the High Income Child Benefit Charge.
- People with income from more than one place, where the job is reconciliation rather than data entry.
- First time filers who have realised, usually in October, that they should have registered by 5 October.
If your return carries undeclared rental income from earlier years, that is a different process with its own route. Our guide to interest on undeclared rental income explains what that actually costs.
Most Cardiff returns are straightforward. The ones that are not usually have a coding problem underneath them.
What goes on a Cardiff Self Assessment tax return?
The form is the same everywhere, but the pages people in Cardiff actually fill in follow a pattern, and knowing which ones apply to you is most of the work of scoping a fee.
Employment. A P60 and, where there are benefits in kind, a P11D. A company car, private medical cover or a beneficial loan all land here, and all three are routinely left off returns by people who assume the employer has dealt with it.
Self employment. Turnover and allowable expenses for the trade, with Class 4 National Insurance computed alongside the Income Tax. Gross trading income over £1,000 is the point at which the pages become compulsory, and that test is on gross income before expenses, so a loss making year can still need a return.
Property. Rental profit computed year by year, with the finance cost restriction applied as a basic rate tax reducer rather than as a deduction. From 2027 to 2028 property income gets its own set of rates, 22, 42 and 47 per cent, and the reducer rises with the lower of them, so a Cardiff landlord’s position is about to change even if nothing about the property does.
Dividends. The allowance is £500 and the rates moved on 6 April 2026 to 10.75 per cent at the ordinary rate and 35.75 per cent at the upper rate. Anyone running a small limited company in Cardiff and taking the usual low salary and dividends mix will see that in this return.
Capital gains. A property or shareholding disposed of in the year, at 18 or 24 per cent, with a £3,000 annual exempt amount. Residential property disposals also carry their own reporting deadline separate from the return, which is the single most expensive thing to discover late.
Everything else. Foreign income, pension contributions and Gift Aid, which extend the basic rate band, student loan repayments, and the High Income Child Benefit Charge for households above the threshold.
If you have two or three of those, the return is not harder so much as longer, and the risk sits in the joins rather than in any one page.
Most of our Cardiff work comes from the independent trades and shops across the city, not from the big employers.
What does filing a tax return late cost?
Filing late and paying late are two separate charges, and both run whether or not you meant it.
The filing side starts at £100 the moment 31 January passes, with no tax due and no excuse needed. From three months late it becomes £10 a day, capped at £900. At six months it is 5 per cent of the tax or £300, whichever is greater, and the same again at twelve months.
What filing a Self Assessment tax return late costs
Cumulative filing penalties only. Paying late is charged separately on top of these.
How it builds. £100 the moment the deadline passes, then £10 a day capped at £900, then 5 per cent of the tax or £300 at six months, and the same again at twelve. The £300 minimums are why a late return with no tax to pay still reaches £1,600.
The payment side is 5 per cent of the unpaid tax after 30 days, again at six months and again at twelve, with late payment interest running at 7.75 per cent as at 10 October 2026. If you cannot pay in full, HMRC’s online Time to Pay route is open to people who owe less than £30,000 and meet the criteria, and it is a great deal easier to arrange in November than on 30 January.
“We recently moved to Cardiff and had questions related to our tax situation. We are very glad to have found Buhir who clearly explained to us how to resolve the issue. Dont hesitate to contact Total Books!”
How does the Cardiff tax return service work, step by step?
Four steps, and the first one costs nothing.
- The call. Fifteen minutes. We ask what income you have, you tell us, and we quote a fixed fee.
- Authorisation. We register as your HMRC agent so we can see what HMRC already holds, including the residence flag and the code.
- The return. We prepare it, flag anything that does not reconcile, and send it to you with the figure and the reasoning.
- Filing and after. We file once you sign off, tell you what to pay and when, and handle whatever HMRC sends afterwards.
“Great digital accountant in Cardiff, very helpful and provided a lot of insightful advice. Highly recommend.”
Want the number before January?
We quote a fixed fee on the call, file as your HMRC agent, and tell you what you owe while there is still time to plan for it.
How much does a Self Assessment accountant in Cardiff cost?
We quote a fixed fee, on the first call, before any work starts. Not an hourly rate that turns into a surprise, and not a headline price with conditions underneath it.
The fee is driven by what is on the return and the state of the records behind it. One employment plus some dividends is a smaller job than a return carrying rental profit, a capital gain and foreign income. Clean bank feeds are a smaller job than a carrier bag. Nothing about the fee depends on how much tax you end up owing.
What the fee includes. Agent authorisation with HMRC. The residence flag and tax code checked before anything is computed. Preparation of the return. A review call where we walk you through the figure and the reasoning. Filing once you have signed it off. The payments on account worked out at the same time. And HMRC correspondence afterwards, coming to us as your agent rather than landing on your mat.
What we do not charge for. The first call. Telling you honestly that your return is simple enough to file yourself, which we do several times a season. Answering a question that takes two minutes.
Get the fee and the scope in one call. If the answer is that you do not need an accountant in Cardiff this year, we will tell you that instead and you will have lost fifteen minutes.
Or call 029 2002 6505
What happens on the first call with an accountant?
People put this off because they imagine being told off. That is not what the call is.
We ask what income you had last year, roughly. Employment, self employment, property, dividends, anything sold, anything from abroad. You do not need figures, and you do not need the paperwork in front of you. Four or five questions is usually enough to know what the return involves.
Then we tell you three things: what the return will include, what the fixed fee is, and what we need from you to start. If there is something awkward in the history, a year never filed or income never declared, we will say what the route through it is rather than pretending it is not there.
Nothing is signed on the call. Most people go away and think about it, and the ones who come back are not doing it because they were pushed.
The first conversation is scoping, not selling. You will know the fee before you leave it.
How do you switch accountants in Cardiff?
About a third of the Cardiff clients we take on in a season already have an accountant. The reasons are consistent: nobody rings them back, the fee moved without warning, or the return turns up on 29 January every year with no chance to question it.
Switching is easier than people expect and it is not a conversation you have to have first. We write to your current accountant for professional clearance and the handover information, register as your agent with HMRC, and pick up from the last filed return. You do not have to explain yourself to anybody, and the timing does not have to wait for a year end.
The one thing worth checking before you move is whether there is work in progress you have already paid for. We will ask.
What is the difference between tax planning and filing a return?
A return is a record of a year that has already happened. Everything that could have changed the number was decided months before it was filed, which is why the clients who pay the least tax are the ones who speak to an accountant in the middle of the year rather than at the end of it.
For small business accountants in Cardiff the useful conversations are narrow and specific. Whether a sole trade has reached the point where a limited company is worth the administration. Whether pension contributions should be taking income out of the 40 per cent band or out of the £100,000 personal allowance taper. Whether a property should be held personally or through a company before it is bought rather than after. Whether a disposal should fall this side of 5 April or the other, with the annual exempt amount at £3,000 and capital gains tax advice in Cardiff rarely sought until the sale has already completed.
None of that is exotic and none of it needs a scheme. It needs the conversation to happen while there is still a decision to make.
Tax planning is a conversation in June. In January all that is left is arithmetic.
We work across Cardiff, the Vale, Newport and Bristol, and we file for people who left the city years ago and never moved their accountant.
Self Assessment in Cardiff: common questions
How much does a Self Assessment accountant in Cardiff cost?
It depends on what is on the return, so we quote a fixed fee on the free call before any work starts. A single employment with some dividends is a smaller job than a return carrying rental profit, a capital gain and foreign income. You will know the number before you commit, and it does not move afterwards unless the scope does.
Do I pay Welsh rates of Income Tax if I live in Cardiff?
Yes, you are a Welsh taxpayer and HMRC puts a C at the front of your tax code. For 2026 to 2027 the Welsh bands match England and Northern Ireland, so the C does not change what you owe. Dividends and savings interest are taxed at the UK rates wherever you live.
I live in Cardiff but work in Bristol. Which rates apply?
Welsh rates, because status follows your main home across the tax year rather than where you earn. The address HMRC holds is what drives the code, so if you have moved recently that is the first thing to check.
I have never filed a return and the 5 October deadline has gone. What now?
Register immediately. HMRC then sets your filing deadline at three months from the date on its letter instead of 31 January. The exposure is a failure to notify penalty, and coming forward before HMRC contacts you is what keeps it at the bottom of the range.
How late can I leave it and still get a Cardiff accountant to take me on?
Practically, December. January is the month everyone remembers, and the work of chasing records, registering for an agent authorisation and reconciling figures with HMRC does not compress well. Earlier also means you know the bill before you have to pay it.
Can you deal with HMRC for me afterwards?
Yes, as your registered agent. Coding notices, payments on account and anything HMRC raises come to us rather than landing on your mat unanswered.
Do you offer tax planning in Cardiff or only tax returns?
Both, and the planning is where the money is. A return records a year that has already happened. Pension timing, the sole trader to limited company question, whether a property is bought personally or through a company, and which side of 5 April a disposal falls on are all decisions that have to be made before the year ends, not after.
Can you take over from my current accountant part way through the year?
Yes, and you do not need to have an awkward conversation with them first. We write for professional clearance and the handover, register as your HMRC agent, and pick up from the last filed return. It does not have to wait for a year end.
Do I need to come into an office?
No. Most Cardiff clients send records electronically and do the review call by phone or video. If you would rather sit down with someone and go through it on paper, that can be arranged.
I am a small business owner in Cardiff, not self employed. Do I still file a return?
Usually yes, if you are a director taking dividends. The dividend allowance is £500 and the rates rose to 10.75 and 35.75 per cent from 6 April 2026, so the salary and dividends mix that worked two years ago is worth re-checking.
I sold a property in Cardiff last year. Is that just on the return?
No, and this is the expensive one. A residential property disposal has its own reporting and payment deadline that runs separately from the Self Assessment return, so people who wait for January have usually already missed it. Tell us about a disposal as soon as it completes, not when the return is due.
Related reading
Bring us whatever you have, even if it is a shoebox and a login you cannot remember. We will tell you what the return involves, what it will cost and what you are likely to owe, before you commit to anything.
Rates, deadlines, penalties and interest stated as published on GOV.UK at 10 October 2026. General information, not advice on your own position. Figures change, so check before relying on them.
