Every year, around 1 million people in the UK miss the Self Assessment deadline, and each one faces an automatic fine, even if they owe no tax. According to HMRC, over 11.48 million people filed their tax return on time for the 2024/25 tax year, but a significant number still did not make the cut.
Tax deadlines in the UK cover more than just Self Assessment; there is also Corporation Tax, VAT, and payroll to think about, each with its own dates and rules. Miss one, and the penalties can build up faster than you might expect. Knowing what is due and when can save your business real money.
Not every business has the same tax deadlines. The dates that matter to you depend on how your business is set up and how it makes money. A freelancer working for themselves has different responsibilities than someone running a limited company. And if your business is registered for VAT, you also have extra reporting to do every few months.
Most of the important tax deadlines in the UK fall across four areas: Self Assessment, Corporation Tax, VAT, and PAYE. Each one has its own date to file paperwork and a separate date to pay what you owe.
The rules about what happens when you miss them are different, too. Even if not all four apply to you right now, it is worth knowing them. Your business can change, and what does not apply today might apply next year.
Here is a simple look at the key dates to keep on your radar:
Self Assessment is the way HMRC collects tax from people whose income is not automatically taxed through their employer. If you work for yourself, own a company and receive dividends, rent out a property, or earn more than £100,000 a year, you will need to file one. It also applies if you earn more than £1,000 from freelance or side work.
The online filing deadline is 31 January every year, and that is also the date your tax payment is due. For the 2024/25 tax year, both land on 31 January 2026. If you prefer to file on paper, that deadline is earlier, on 31 October.
Miss either date and HMRC will send an automatic £100 fine, even if you do not owe any tax. According to HMRC, daily £10 penalties can start after three months, building up to £900 on top of anything else you already owe.
The longer you leave it, the more expensive it gets. A missed deadline does not just mean one fine. HMRC adds more charges at three months, six months, and twelve months. Filing as quickly as possible, even if you cannot pay straight away, will always save you money in the long run.
This is the part that catches most people off guard. Payments on account are early payments towards your next year's tax bill. You make two each year, one on 31 January and one on 31 July.
In your first year, this can feel like two large bills arriving very close together. Setting money aside regularly makes it much more manageable. Our tax compliance services can help you plan around these dates so nothing takes you by surprise.
Corporation Tax is a tax that limited companies pay on the money they make. If your business is set up as a limited company, this applies to you. The good news is that it is not as confusing as it sounds once you understand how the dates work.
Unlike Self Assessment, Corporation Tax does not have one fixed date that applies to everyone. Your deadline depends on when your company's financial year ends, which is called your accounting period. Here are the two key dates to remember:
These are two separate deadlines, and many business owners mix them up. A simple example: if your accounting year ends on 31 March, your Corporation Tax payment is due by 1 January the following year, while your Corporation Tax return does not need to be filed with HMRC until 31 March the following year.
Many businesses get caught out because the payment date actually comes before the filing deadline. This means you need to work out how much you owe and pay it before your paperwork is even due. Keeping your accounts up to date throughout the year makes this much easier to manage. According to HMRC Corporation Tax guidance, late payments result in interest charges that start building from the day after the deadline passes.
Missing the payment deadline means HMRC starts charging interest straight away. The longer it goes unpaid, the more it costs. Even if your company made very little profit, you are still expected to file a return and pay on time.
Our tax compliance services cover Corporation Tax preparation and filing from start to finish. And if you want your company's accounts and filing deadlines managed properly throughout the year, our company secretarial services can take care of that too.
VAT stands for Value Added Tax. It is a tax that businesses add to the price of most goods and services they sell. If your business earns more than £90,000 a year in taxable sales, you must register for VAT with HMRC. Once you are registered, you collect VAT from your customers and pass it on to HMRC regularly.
Most VAT-registered businesses submit a VAT return every three months. The deadline to send your return and pay what you owe is one month and seven days after the end of each quarter. So if your quarter ends on 31 March, everything is due by 7 May.
Missing this date can lead to penalty points and fines, which add up the more times it happens. According to HMRC VAT guidance, repeated late submissions can result in financial penalties even if the amounts owed are small.
Most businesses now have to file their VAT returns using Making Tax Digital-compatible software. This is a legal requirement for the majority of VAT-registered businesses. It means you cannot simply fill in a form and send it by post. Your accounting software needs to connect directly to HMRC's system. Our small business bookkeeping services can help you keep your records in order so your VAT returns are always ready on time.
Some smaller businesses choose the VAT Annual Accounting Scheme, which lets you file just one return per year instead of four. You still make payments throughout the year, but the admin is much lighter. If you are not sure which VAT arrangement suits your business best, speaking to an accountant is a good place to start.
PAYE is the system HMRC uses to collect Income Tax and National Insurance from employees. If you have staff on your payroll, you are responsible for running PAYE correctly and reporting to HMRC every single month. Unlike most other tax deadlines, payroll does not give you a once-a-year reminder. The dates keep coming, month after month, all year round.
Here are the key PAYE deadlines every employer needs to know:
Missing any of these dates is costly. HMRC charges penalties for late or missing submissions, and these can add up quickly the longer they are left. Even being one day late with a Full Payment Submission can trigger a fine. And if you are late paying PAYE, HMRC adds interest on top of what you owe.
For small businesses managing everything on their own, keeping up with monthly payroll reporting can feel like a lot. It sits on top of running your business, dealing with customers, and managing your own finances.
Our payroll services take this off your plate completely, handling your submissions, payslips, and payments so every deadline is met without you having to think about it. And with HMRC's employer guidance available online, you can always check the rules if something is unclear.
When a tax deadline passes, and nothing has been filed or paid, HMRC does not wait around. Penalties go out automatically, and the longer things are left, the bigger the bill gets.
The penalty structure for late Self Assessment returns works like this. Miss the 31 January deadline by just one day, and you get an automatic £100 fine, even if you owe no tax at all. After three months, HMRC adds daily £10 charges that can reach up to £900.
After six months, there is an extra charge of £300 or 5% of your unpaid tax, whichever is more. After twelve months, that same charge is added again. On top of all that, HMRC charges interest on anything you still owe. You can check the full breakdown on the HMRC Self Assessment penalties page.
For Corporation Tax, there are no fixed fines for paying late. Instead, HMRC charges interest every day from the moment the payment is overdue. For VAT, HMRC now uses a points system.
Each time you miss a deadline, you collect a point. Once you reach a certain number of points, a £200 fine is issued and keeps being added for every late submission after that.
Most penalties are completely avoidable. Keeping your records tidy throughout the year means you are never scrambling at the last minute. Small business bookkeeping services keep your accounts up to date all year round, and tax compliance services make sure every deadline is met on time.
Knowing your tax deadlines is only half the job. The other half is making sure your records and finances are ready well before those dates arrive. If your paperwork is all over the place, even the best intentions will not save you from a fine.
Here is a simple way to stay on top of it all, step by step.
At the start of each new financial year, write down every deadline that applies to your business. Include filing dates, payment dates, and any HMRC submission deadlines. Then set a reminder at least one month before each one.
This gives you enough time to gather what you need, spot any problems early, and get help if you need it. A free tool like Google Calendar works perfectly for this.
Do not wait until the end of the year to look at your finances. Businesses that check their income and spending every month are far better prepared when tax time comes around. There are no last-minute surprises, and cash flow is much easier to manage. Red Fish Accountancy’s management information services give you clear, regular reports so you always know where your business stands financially.
Good records make everything easier. When your invoices, receipts, and expenses are organised and up to date, preparing a tax return takes a fraction of the time. Our small business bookkeeping services keep everything in order throughout the year, so nothing gets missed when deadlines come around.
Some deadlines, like filing your annual accounts with Companies House, are easy to forget when you are busy running a business. Our company secretarial services take care of these obligations for you, making sure every statutory deadline is met without you having to keep track of it yourself.
Tax deadlines in the UK come around faster than most people expect, and the penalties for missing them are not small. The good news is that you do not have to keep track of all of it on your own.
Red Fish Accountancy helps small business owners, freelancers, company directors, and landlords across the UK stay on top of their obligations all year round. Whether you need help with tax compliance, payroll, or bookkeeping, our team is ready to make sure nothing gets missed and no unnecessary fines land on your doorstep.
