Self Assessment

Your tax return, sorted — no January dread

Your personal tax return prepared, reviewed and filed properly — every allowance claimed, every deadline met, and not a single late-night scramble in sight.

Self Assessment is how HMRC collects tax that isn't taken automatically through PAYE — on self-employment, rental income, dividends and more. You file an SA100 return each year declaring that income. We prepare, check and file yours, claiming every allowance and relief you're owed.

The plain-English promise

File it once, file it right

Self Assessment catches out more people than any other tax. The rules on what to declare, what you can deduct and when to pay are genuinely confusing — and the penalties for a slip are anything but. We turn a stressful annual chore into something you barely have to think about.

Whether you're a landlord, a higher-rate earner with dividends, self-employed, or juggling a bit of side income, we gather the details, prepare your SA100, and check it against every allowance and relief you're entitled to. Then we file it with HMRC and tell you exactly what to pay, and when.

No frantic hunt for paperwork on 30 January, no guessing, and no paying more than you should. Just a return that's right, in on time, and completely off your mind.

Preparing a personal Self Assessment tax return
Is this you?

Any of this sound like you?

  • January arrives and the receipts still aren't sorted.
  • You're a landlord and unsure what you can actually deduct.
  • Dividends and a salary together have pushed you into higher-rate territory.
  • You've picked up side income and don't know if you need to declare it.
  • Last year's payments on account came as a horrible surprise.
  • You suspect you're missing reliefs but wouldn't know where to look.

If it does, this is precisely the yearly headache we make disappear.

What's included

Everything your SA100 needs

A complete, hands-off service from your paperwork to a filed, HMRC-accepted return.

SA100 preparation & filing

Your full personal return prepared, checked and filed directly with HMRC online.

Rental income & property

Landlord income and allowable costs handled properly, including the finance-cost tax credit.

Dividends & higher-rate

Salary, dividends and savings pulled together so your position is worked out correctly.

Reliefs & allowances review

We check pensions, gift aid, marriage allowance and more, so nothing you're due is left on the table.

A clear figure, early

You'll know what to pay and when — including payments on account — with time to plan for it.

HMRC dealt with for you

We're your agent with HMRC, so queries and correspondence come to us, not you.

How it works

Three steps to a filed return

  1. You share the details

    Send us your income, expenses and any statements — a simple checklist tells you exactly what we need, nothing more.

  2. We prepare and check

    We build your return, claim every relief you're due, and run the final figure past you in plain English before anything is filed.

  3. We file and confirm

    Once you approve it, we submit to HMRC and confirm what to pay and by when, well ahead of the deadline.

Key Self Assessment dates

Register for Self Assessment by 5 October after the tax year you had untaxed income. Your online return and any tax owed are due by 31 January. If you make payments on account, they fall on 31 January and 31 July. Miss the January deadline and HMRC charges an automatic £100 penalty — we make sure you never do.

Questions, answered

Common questions about Self Assessment

You generally need to file if you're self-employed, a company director, a landlord, earn significant dividends or savings income, or have income HMRC doesn't tax automatically. Higher earners and anyone liable for the High Income Child Benefit Charge often need one too. Not sure? Tell us your situation and we'll confirm in minutes.

Payments on account are advance instalments towards next year's tax bill, each worth half of your previous year's liability. They fall due on 31 January and 31 July. They surprise a lot of people the first time, so we always flag them early and show you the full picture before the bill lands.

You can deduct running costs like letting-agent fees, repairs, insurance, ground rent and allowable maintenance. Mortgage interest no longer counts as a straight deduction — instead you get a 20% tax credit on finance costs. We apply the rules correctly so your rental profit, and your tax, are right.

HMRC charges an automatic £100 penalty the moment you miss 31 January, even if you owe nothing. After three months daily penalties start adding up, with further charges and interest beyond that. With us handling your dates, late filing simply isn't on the cards.

Goes well with

You might also need

Ready to leave January panic behind?

Book a free consultation and we'll review your situation, check you're claiming everything you should, and give you a clear, fixed quote to take your return off your hands — no obligation.

We reply within one working day.

In our clients' words

Relationships that outlast the tax year

We came to HK Accountax mid-panic before a VAT deadline and left with a plan, a proper system, and a lot less dread. Pankaj explains things without making you feel daft.
S Sarah T.
E-commerce Founder, Marlow
Switching over was painless — they sorted everything with our old accountant. Now we actually get told about tax bills in advance instead of the week they're due.
J James R.
Director, Facilities Company
My self-assessment used to eat a whole weekend. Now I send my figures over and it's done properly, on time, with reliefs I didn't even know I could claim.
A Aisha K.
Freelance Consultant, High Wycombe
Straight-talking, quick to reply, and genuinely on our side. It feels like having a finance person in the family rather than a faceless firm.
M Mark & Lucy P.
Landlords, Buckinghamshire
They set up our company, got us on Xero, and mapped out the whole first-year compliance calendar. Exactly the steady hand a new business needs.
D Daniel O.
Start-up Founder, Thames Valley
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