Filing a tax return for the first time might sound tricky, but it doesn’t have to be.
Whether you’re self-employed in Cardiff, earn rental income, or have investments, this guide will help you feel confident about completing your tax return.
What is a tax return, and who needs to file one?
What is a tax return?
A tax return is a form that tells HMRC (the UK government tax office) how much money you made in a year. You also include information about expenses, tax reliefs, and other deductions, so HMRC can figure out how much tax you owe - or if they owe you money (that would be nice for a change)!
Who needs to file a tax return?
You need to file a tax return if:
- You’re self-employed (e.g., a freelancer, consultant, or small business owner).
- You made more than £2,500 in untaxed income after allowable expenses, or £10,000 before allowable expenses. An example of untaxed income is renting out a property.
- You made money from savings, investments, or overseas income.
- You want to claim tax relief (e.g., on donations or pensions).
For a full list, check HMRC’s website to see if you need to file a tax return.
Interactive tax return checklist
Do you need to file a tax return?
Use this quick checklist to help decide:
- Did you make more than £12,570 this tax year?
- Do you have untaxed income, like from renting out a property or freelance work?
- Do you earn from savings, dividends, or investments?
- Are you claiming tax relief (e.g., on donations)?
If you answered yes to any of these, you’ll likely need to file a tax return.
Confused about complex tax rules?
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Preparing for your tax return
How to register for self-assessment
If you’re filing for the first time, you’ll need to register for self-assessment with HMRC.
- Go to the HMRC self-assessment registration page.
- Create a Government Gateway account and provide details like your National Insurance number.
- Once registered, HMRC will send you a Unique Taxpayer Reference (UTR) number by post. This is your unique code for all tax returns.
Registration deadline
Make sure to register by 5th October after the end of the tax year in which you started earning untaxed income.
Watch this video for a step-by-step guide on how to register if you’re self-employed.
What documents do you need for a tax return?
Before starting your tax return, you’ll need to gather important documents. Here’s a list of what to prepare:
Personal information
- National Insurance number
- Unique Taxpayer Reference (UTR)
Income records
- Employment income. P60 form from your employer, or P45 if you changed jobs.
- Self-employment income. Records of what you earned and spent.
- Rental income. If you rent out property in Cardiff, or anywhere else for that matter, make sure that you gather records of rent and any related expenses (like repairs).
- Savings and investments. Bank statements showing interest earned or dividends received.
- Pension income. Records of any state or private pension received.
Expense records
If you’re self-employed, you can claim expenses to reduce your tax bill. Common deductible expenses include:
- Office supplies, travel, and any business-related purchases.
- Keep receipts to back up your claims!
Different filing scenarios
Self-employed freelancer
If you’re a freelancer, you’ll need to report all your earnings from clients, minus any expenses like travel costs or software. You can also claim tax relief on business expenses.
Landlord
For landlords, you’ll report rental income and expenses like maintenance, repairs, and property management fees. This reduces your taxable income.
Investors
If you make money from investments, such as dividends or capital gains, you’ll need to declare them and possibly pay capital gains tax.
High earners
If you earn over £150,000, even if it’s through a regular job, you’ll need to file a return. You’ll also likely pay additional tax.
Side hustles
If you run a side hustle (e.g., selling things online, or freelance work), you need to report this income even if it’s part-time.
Expats
If you’re an expat with foreign income, you may need to declare it in the UK, especially if it wasn’t taxed abroad.
Filing your tax return in Cardiff
Filling out your tax return can be done online or by paper, though most people prefer the online option.
Step-by-step guide for online filing
- Log in to your HMRC account using your Government Gateway details.
- Start your self-assessment. Choose “File Tax Return.”
- Input personal details. Fill in your National Insurance number, UTR, and other personal info.
- Declare your income. Report all your earnings - employment, self-employment, savings, rental, etc.
- Claim expenses. If you’re self-employed, list your allowable expenses.
- Check for tax reliefs. Include any tax reliefs or allowances (e.g., for charitable donations).
- Submit. Review your return and hit submit.
Deadlines
- Paper return deadline. 31st October
- Online return deadline. 31st January
Common issues when filing a UK tax return
Here’s what to do if you run into problems:
Error messages
If you see an error while filing online, clear your cache or try again later. If the problem persists, contact HMRC support.
Forgotten UTR
If you’ve misplaced your UTR, log into your HMRC account to find it, or check any letters HMRC has sent you.
Incorrect information filed
If you realise you made a mistake, you can amend your return within 12 months of the original deadline.
Consider filing early to avoid stress
Filing early can save you a lot of stress. Here’s why:
- Avoid the rush. If you file early, you avoid the last-minute panic. Accountants in Cardiff are very busy during tax season, so you will typically get faster responses if you file early.
- Get your refund sooner. If HMRC owes you money, filing early means you get it back faster.
- Avoid penalties. If you file early, you don’t have to worry about missing the deadline and being fined.
What to do if you can’t afford your tax bill
If your tax bill is higher than expected and you can’t afford to pay it all at once, you can set up an HMRC payment plan.
Time to Pay arrangement
With a Time to Pay plan, you can spread your payments out over time. Just contact HMRC, and they’ll help set up a manageable payment schedule.
What happens if you don’t file your tax return on time?
Penalties for late filing
- £100 fine if you’re up to 3 months late.
- More fines if you continue delaying.
- Interest charges on any tax owed after the 31st January payment deadline.
How to get money back from HMRC
Did you know you might be owed a refund? Here’s how to claim one:
Overpayments
If you’ve paid too much tax (like through employment), you can get a tax refund. Keep records of any employment expenses you’ve claimed.
How to claim a refund
Once HMRC reviews your return, they’ll calculate if you’re due a refund. Refunds normally arrive within 5-10 business days if you filed online, but can take as long as 10 weeks.
Final thoughts
Filing a tax return might seem overwhelming, but by following these steps, you’ll be able to handle it with confidence.
About the author
Jon Dell is a Chartered Accountant who qualified at PwC, the largest professional services firm in the world. He has worked internationally as well as across the public and private sectors. He now has his own practice where he works on both personal and Limited company taxation services. His particular focuses are property income and taxation as well as medical outsourcing companies.
