Self assessment may feel like a chore if you’ve never done it before. You’re expected to fill in forms, track income, remember deadlines, and pay what you owe on time. It sounds straightforward, but many people worry about missing a detail or filing late. We understand that this can be a stressful process for business owners, freelancers, and individuals alike. In this post, we’ll explain the fundamentals of self assessment, show you who needs to file, and share our best tips so you can avoid penalties and submit your tax return with confidence.

Why it can feel overwhelming

Every year, thousands of people scramble to submit their tax return, only to find they’ve misunderstood the requirements. If you’re new to self assessment, you might wonder whether it applies to you, which forms you need, or what happens if you’re late. According to HMRC, around 12.2 million people in the UK are required to file a self assessment return, and new filers often misjudge how long it takes to pull everything together. This can lead to penalties, overdue bills, and sleepless nights.

When stress takes over

Imagine finding out you owe extra money because you missed the deadline or you didn’t include some income stream. That sense of uncertainty and the pressure of paying more than you expected can throw your finances off balance. Missing key paperwork or forgetting to track allowable expenses can mean overpaying tax – money you could have kept in your business or used to grow your operations. Instead, you’re left feeling overwhelmed. For owner-managers who are busy running their companies, filing a tax return can fall to the bottom of the to-do list, only to create last-minute panic in January.

Moving past the roadblocks

We believe it doesn’t have to be this way. Self assessment becomes simpler when you break it down into easy steps. Below, we’ll cover who needs to file, key deadlines, and some helpful advice. At Stapletons, we work closely with our clients on a more personal basis, so if you’d like one-to-one support, please let us know. Think of us as your partner in building a long-term relationship that makes tax less daunting.

What is self assessment?

Self assessment is HMRC’s system for collecting Income Tax from individuals who don’t have it automatically deducted through PAYE (Pay As You Earn). This includes self-employed people, directors of limited companies (in many cases), landlords who rent out property, and individuals with untaxed income. You may need to file a return if you earn money outside regular employment – even if it’s a small side project.

Some common scenarios where you need to submit self assessment:

• You have self-employed earnings of more than £1,000 (after allowable expenses).
• You’re a landlord earning rental income above £1,000.
• You or your partner receive Child Benefit, and one of you has an income over £50,000.
• You have to claim tax relief on pension contributions or charitable donations.
• You’re a company director (though there are exceptions).

Not sure if self assessment applies to you? We can help you figure out if you need to file.

Important deadlines and penalties

For the 2024/25 tax year (6 April 2024 to 5 April 2025), you must submit your paper return by 31 October 2025. If you plan to file online, the deadline is 31 January 2026. You must pay your tax by 31 January as well.

Late filing penalties start at £100 if you’re up to three months late. Beyond that point, penalties increase, and interest accumulates on outstanding amounts. Daily penalties may apply if you still haven’t filed after six months, which can mount up. Simply put, filing on time helps you avoid extra fees.

Getting started: Records and information you’ll need

Collect records as you go: Gather all information on income and outgoings throughout the year. If you’re self-employed, this includes all invoices, receipts, and bank statements. If you’re a landlord, keep track of your rental statements and any repairs or maintenance costs. By staying organised, you’ll save time and reduce the risk of mistakes.

Check your Personal Allowance: For most people in the 2024/25 tax year, the Personal Allowance is £12,570. You won’t pay Income Tax on the first £12,570 you earn. Above this amount, you pay 20% up to £50,270, then 40% from £50,271 to £125,140. Earnings above £125,140 are taxed at 45%.

Include all income streams: Self assessment is meant to capture all your taxable income. That might be salary from employment, profit from self-employment, rental income, dividends from shares, or interest on savings. You could be liable for penalties or tax investigations if you leave anything out.

Self assessment tips for first-timers

1. Register early: If you haven’t filed before, register for self assessment with HMRC as soon as you believe you’ll need to submit a tax return. You’ll receive a Unique Taxpayer Reference (UTR) number, which you need to file.
2. Consider opening a separate business bank account: If you’re self-employed, having a separate account makes it easier to track your income and expenses. This is especially helpful if you’re a contractor within the Construction Industry Scheme (CIS). CIS subcontractors often have tax stopped at source, so clear records are vital to ensure you claim back anything you’re owed.
3. Keep track of allowable expenses: Many day-to-day costs can be claimed as allowable expenses if they’re “wholly and exclusively” for business. This can include office supplies, some travel, and utility bills (if you work from home). Make sure you keep receipts and invoices to support your claims.
4. Plan ahead for your tax bill: Once you have a rough idea of your taxable profit, set aside money each month. This helps you avoid surprises when the payment deadline arrives. We encourage our clients to budget for their tax liabilities in stages.
5. File online for greater flexibility: HMRC’s online system provides immediate submission and a bit more time (until 31 January) compared to the paper deadline of 31 October. You can also view your calculation instantly, which shows how much you owe.
6. Ask for help if needed: If you’re unsure about anything, it’s better to check with an accountant than guess. We’re here to offer practical guidance and explain in plain English. When you work with us, you’re not just getting a set of accounts – our aim is to become your long-term partner, supporting your business goals as you grow.

How self assessment helps your business

Self assessment isn’t only about paying tax. It’s also an opportunity to get an overview of your earnings and expenses, which can reveal how your business is performing. If you notice unusual dips in your income or a rise in certain expenses, this can prompt you to adjust your budget and forecast for the coming year.

We encourage small business owners to use self assessment time as a regular “check-in” on overall financial health. Are you claiming all allowable expenses? Is your profit in line with your targets? Have you factored in payroll for staff, if any? When you treat your tax return as part of a wider review, you’ll learn more about how your business is doing.

Next steps

The main message is that you don’t have to tackle self assessment alone. With good planning and the right support, you can avoid penalties, deadlines, and the fear of making an error. We want our clients to feel at ease discussing their finances, which is why we take the time to build relationships rather than simply crunch numbers.

If you’d like extra support with self assessment, or if you have questions about whether you need to file, let us know. We’re always here to help.