January 2027 Tax Deadline: What UK Business Owners Need to Know

The countdown to 31st January 2027 has begun

January might still feel a long way off, but for UK business owners, the next major tax deadline is approaching faster than expected.

The deadline for submitting your online Self Assessment tax return and paying any outstanding tax for the 2025/26 tax year is 31st January 2027.

If you’re a sole trader, self-employed professional or company director with additional income to declare, leaving your tax return until the last minute can create unnecessary stress, cash flow problems and potentially expensive penalties.

The good news is you don’t need to wait until January to get everything sorted.

Taking a little time now to organise your finances, review your records and understand what you owe can make the entire process much easier.

Here are five things business owners should be doing now to prepare.

1. Get Your Financial Records Organised

One of the biggest reasons people delay their tax returns is that they haven’t organised their financial records.

Trying to gather twelve months of invoices, receipts, bank statements and business expenses in January can quickly become overwhelming.

Start by bringing together your financial information for the 2025/26 tax year, which ran from 6th April 2025 to 5th April 2026.

Make sure you have:

• Records of all business income and sales.
• Business expense receipts and invoices.
• Bank statements and relevant financial records.
• Records of any additional income.
• Details of pension contributions and other relevant tax reliefs.
• Records of dividends, interest and other taxable income where applicable.

Having everything in one place makes it easier to complete an accurate tax return and identify any information you might still be missing.

2. Understand What Tax You Actually Owe

One of the biggest financial mistakes business owners make is waiting until their tax return is submitted before thinking about how they will pay the bill.

Your Self Assessment tax bill may include Income Tax, National Insurance contributions and other amounts depending on your circumstances.

You may also need to make payments on account towards your next tax bill.

These are advance payments towards your following year’s tax liability, usually due twice a year:

• 31st January 2027: First payment on account, alongside any balancing payment.
• 31st July 2027: Second payment on account.

Not everyone needs to make payments on account, but if they apply to you, they can significantly affect your cash flow.

Reviewing your estimated tax liability now gives you more time to prepare financially rather than scrambling to find the money when January arrives.

3. Check That You’re Claiming All Eligible Business Expenses

Are you claiming all the business expenses you’re entitled to?

Overlooking allowable expenses can mean paying more tax than necessary.

Depending on your business structure and circumstances, potentially allowable expenses may include:

• Office supplies and business equipment.
• Software subscriptions and business tools.
• Professional fees and accountancy costs.
• Business travel and qualifying mileage.
• Marketing and advertising costs.
• Certain home-working expenses.
• Business insurance.

However, not every purchase automatically qualifies as a business expense. Some costs have specific rules, restrictions or different tax treatments.

It’s worth reviewing your expenses with an accountant to ensure you’re claiming the reliefs available to you while keeping your records accurate and compliant.

4. Don’t Forget the Penalties for Missing the Deadline

Missing the Self Assessment deadline can become expensive, even if you don’t owe any tax.

HMRC applies an initial £100 late filing penalty if your tax return is submitted after the deadline.

If your return remains outstanding for more than three months, additional daily penalties of £10 can apply, up to a maximum of £900.

Further penalties may apply after six and twelve months.

Late payment can also result in interest and additional penalties.

The important thing to remember is that submitting your tax return and paying your tax bill are two separate responsibilities. You need to make sure both are dealt with on time.

5. Speak to Your Accountant Before January

You don’t have to manage your tax return alone.

Getting professional support before the January rush gives you more time to resolve missing information, check your figures and understand your tax position.

An accountant can help you:

• Review your financial records.
• Identify eligible expenses and tax reliefs.
• Calculate your estimated tax liability.
• Prepare and submit your Self Assessment return.
• Plan for upcoming tax payments.
• Identify potential issues before they become problems.

If you’re a company director, remember that your personal Self Assessment obligations are separate from your company’s Corporation Tax return and statutory accounts deadlines.

It’s important to keep both sets of responsibilities in view.

Important Dates to Remember

Here are the key dates to keep on your radar:

These dates relate to the 2025/26 Self Assessment tax year. The paper filing deadline of 31st October 2026 has already passed.

You can find the official guidance on the HMRC Self Assessment deadlines page.

Don’t Leave Your Tax Return Until January

The January tax deadline might seem far away, but preparing early can make a significant difference to your business finances.

Getting your records organised, understanding your tax liability and making sure you’re claiming eligible expenses can help you avoid unnecessary stress and plan your cash flow more effectively.

Remember, good financial management isn’t just about meeting deadlines. It’s about knowing where your business stands and making informed decisions throughout the year.

Need help getting your finances ready for January?

At Future Cloud, we help UK business owners stay on top of their accounts, tax obligations and financial planning.

Whether you need help preparing your Self Assessment tax return, organising your bookkeeping or understanding your tax position, our team is here to help.

Get in touch with Future Cloud today and get ahead of the January tax deadline.

Get in touch with our team today to find out how we can support you!

info@future-cloud.co.uk

Your friendly, forward-thinking accountants!

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